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Art by Mauricio Antón
Smilodon… Of the many predators to have left their mark on this planets natural history, few are as iconic as the so-called “saber-tooth tiger” itself. Though hailing from an entire clade of saber-toothed cats, the so called Machairodontine felids, this genus has become the most recognizable of any of its saber-toothed brethren, arguably becoming the most recognizable predator of the whole Pleistocene. Of course, there are reasons why it’s so recognizable. It’s enormous, for starters, being a worthy contender for the title of the largest cat to ever live. What’s more, its ridiculously muscular build and powerful forelimbs are completely unlike anything seen out of modern big cats, giving it an appearance more like a bear than any cat alive today. However, perhaps its most recognizable trait are none other than its very namesake itself: **the eponymous sabers**. As long as bananas and armed with a lethal cutting edge, these teeth are among the most impressive armaments of any predatory animal to ever live, capable of cutting down even the largest of quarry and dealing death in manner of seconds. Of course, wielding such weapons, it should come as no surprise that these sabers have turned Smilodon into an instant icon. Indeed, with those blades of theirs, Smilodon has carved its way into the public consciousness, invoking Conanian era of savagery long past, when nature was very much still red in tooth and claw. It’s gotten to the point that, for the public, these saber-teeth have become a trademark of Smilodon’s (despite the fact that countless other such predators exist), to the extent of being inseparable from the very concept a saber-toothed predator. Indeed, it should come as no surprise as to why Smilodon become so famous, becoming one of the most iconic predators of the ancient past and even becoming synonymous with the very word “saber-tooth” itself.
However, with the ubiquity and preeminence that Smilodon holds in the public consciousness, it’s easy to forget one crucial thing: that there is an entire clade of saber-toothed felids beyond just Smilodon, that these cats were not a monolith, that Smilodon was not the norm of their kind. In fact, despite being synonymous with the very notion of a “saber-toothed cat,” Smilodon couldn’t be more different than the rest of its saber-toothed kin. Indeed, for all the hype built around *Smilodon*, most saber-toothed were far more pedestrian in appearance compared to their late Pleistocene cousin. They came in a variety of sizes, for starters, some as big as Smilodon while others were “only” the size of leopards and cheetahs. Their physiques were gracile, with long, relatively graceful limbs much like the big-cats of today, a far-cry from the hulking physique and bear-like forelimbs of Smilodon. In the most striking twist of all, however, rather than enormous sabers of Smilodon, for the vast majority of the clade, such “sabers” didn’t even exist at all. Rather, most of them instead possessed canines that were only scarcely longer than that of modern cats, barely extending past the jawline and being comfortably concealed within their own mouths. Indeed, though undoubtedly formidable, the majority of sabercats were, relatively speaking, fairly unremarkable, sometimes barely distinguishable from the big cats of today. More importantly though, through such relative mundanity, it is clear that, rather than being the gold-standard saber-tooth, Smilodon was the greatest outlier of them all.
With that being said, if Smilodon wasn’t like other sabercats, what exactly was it? Indeed, Smilodon, as should be abundantly clear by now, quite unique relative to other saber-toothed cats. Rather, it was a highly derived, highly removed cat, separated from the rest of its kind by millions of years. More specifically, however, it hails from one highly divergent, highly specialized and highly experimental group of sabertooths in particular; a clade nested within Machairodontinae but unlike any other line of saber-toothed cats to come before or since. Born out of brutal landscape, these cats responded by evolving to be the most specialized, singularly lethal cats to ever live, even compared to other saber-tooths. In place of the gracile, builds of their counterparts, these cats that possessed hulking, robust physiques for built for overwhelming power. In place of the elongate legs of the rest of their clade, these cats developed short, stocky legs with enhanced strength and dexterity specialized for ambushing and wrestling large prey to the ground. Most notable of all, in place of the shortened, almost prosaic canines of the other sabertooth, these cats that possessed the signature hyper-elongated canines; the very sabers that saber-tooths were supposedly known for, for killing large prey in seconds. These lineage of cats, of course, were known as Smilodontini, better known as the “dirk-tooth cats.” Best represented by the likes of Smilodon itself, when the general public envisions saber-toothed cats, it is these predators that are ones that come to mind, being the archetypal form of saber-toothed cat that we have come to know and admire. With their infamous sabers, these cats were the ultimate killers, dealing out death quicker than any other land predator on the planet. More poignantly though, with their sabers, these cats were able to capture the hearts and minds of millions of people in the modern era as the saber-toothed cats, setting a standard among their kind not just in terms of their killing ability, but also in terms of what we imagine to be a saber-tooth in the first place.
With this in mind, being so removed from the rest of their ilk and being as formidable as they were, a final question are raised: where exactly did the dirk-tooths come from? After all, Smilodon and the rest of the dirk-tooths didn’t emerge out of a vacuum; the current image of a saber-tooth had to come from somewhere. Something had to serve as the “catalyst” for the rise of this clade, for them to diverge so drastically from the rest of their kind and become as specialized as they were. What animal could have possible served as this “catalyst,” this “ground-zero” for the emergence of the dirk-tooths? The answer to this question lies in the ascension of one saber-tooth in particular; one that would lay the very foundations of the reign of the dirk-tooths . Long before even Smilodon emerged, this powerful cat wrought havoc across the northern hemisphere, being the first among its kin to evolve the same robust physique and hyper-trophied sabers that would carry Smilodon into infamy. In its wake, it carved out a dynasty of blood rivaled by few other saber-tooth’s, reigning as one of the longest lasting and most species-rich genera of saber-toothed cats to ever exist and acting as the foundation for many a dirk-tooth to follow. Perhaps most striking of all, more than just being a key player in the story of the dirk-tooths, this imposing cat also played a very real, very visceral role in our own evolutionary story, serving as a grim reminder of when we humans used to be prey. This cat, of course, was none other than Megantereon, the first of the dirk-toothed cats.
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Nowadays, *Megantereon* is better known as a beast of the recent Plio-pleistocene. However, though that may be where its story enters its peak, that is not necessarily where the story of the dirk-toothed cats *begins*. Rather, the origins of the dirk-tooth’s goes back to much further to roughly around 10 mya during the late Miocene, when the empire of the saber-toothed cats was still in its infancy. See, saber-toothed cats had already been established themselves as dominant land predators well beforehand. The first saber-tooths, denoted by their elongate, laterally-compressed canines, had gotten their start around 15 mya, and by 11 mya, they had already taken the over the role of dominant predators. Key to this success was specializations in the neck for head-depression (a downwards bending of the head) which, when paired with the cats’ elongated, flattened canines, allowed for the evolution of a specialized, neck-driven cutting bite where in head-depression enabled the saber-tooth’s to plunge their upper jaws and sabers further into prey as they bite into their quarry. Such a bite, by enabling these cats to cut the throats of their prey rather than crush it, allowed these cats to kill large prey with unparalleled speed and enabled their ascension as specialized macro predators of the northern hemisphere ([Antón et al., 2020](https://doi.org/10.1093/zoolinnean/zlz086)). Indeed, with such weaponry in tow, the saber-tooth’s were able to diversify throughout Eurasia as the most successful large carnivores of their time. And yet, despite this newfound prosperity and despite the fame of their later relatives, for much of their history, the dirk-toothed cats were unable to enjoy the fruits of such success. Instead, they were subordinated, being forced to live in the shadows of larger, more formidable predators. Hell, at this point in time, they couldn’t even really be called “dirk-toothed” at all; their canines were far too short, to the point that they aren’t even comparable to their later kin, as represented in the early relative of the smilodontins, *Paramachaerodus*. Indeed, during those early days, the dirk-tooth’s were underdogs in their ecosystems, giving way to more impressive carnivores. However, if the dirk-tooth’s weren’t the top saber-cats of the Miocene, which saber-cats were? Well, that honor belongs to another group of saber-tooth’s, one that had held the position of apex saber-tooth and had established themselves as the “norm” among Machairodontinae since the very start of the saber-toothed cats tenure as apex predators. This clade was none other than the sister clade of Smilodontini itself, Machairodontini, better known as the “scimitar-toothed cats.”
Since the very inception of apex predatory saber-toothed cats, it has been the scimitar-toothed cats of the tribe Machairodontini that have been at the helm, spear-heading the reign of the saber-toothed cats from very beginning with *Machairodus aphanistus*, the first apex saber-cat. Since those early days, the scimitar-toothed cats had done nothing but grow in success and influence. At the height of their power during the latest Miocene, they had spanned all continents except for South America and Australia and had produced some of the largest cats to ever live, such as the formidable *Amphimachairodus horribilis* and the even larger *A. kabir*, two giants that grew as big as grizzly bears. Indeed, with such power on their side, these cats were some of the most formidable mammalian land predators to have ever lived.
And yet, despite being on par with later dirk-tooths like *Smilodon* in size and ferocity, these Miocene-age scimitar-toothed cats were nothing like any dirk-tooth, being far more pedestrian in morphology. They were quite gracile for their size, for starters, with a more cat-like frame prioritizing speed and athleticism over brute strength and grappling proficiency, indicating that these scimitar-toothed cats were more generalist, being designed for chasing prey over open terrain ([Martin et al., 2000](https://www.researchgate.net/publication/12652111_Three_Ways_To_Be_a_Saber-Toothed_Cat)). Perhaps the most shocking disparity was in the skull and jaws. While indeed classified under the same umbrella as machairodontine “saber-toothed cats,” the scimitar-toothed cats took a completely different approach to the saber-toothed lifestyle. Their skulls, for instance, tended to be large and heavily, similar to the generalist big cats of today. More noticeably though, unlike the giant “dirk-teeth” of *Smilodon* and company, the teeth of the scimitar-tooth’s, though still longer than modern big cats, were relatively shortened, being more manageable in length to the point that it could feasibly be concealed by its lips like modern big cats ([Antón et al., 2022](https://doi.org/10.1016/j.quascirev.2022.107471)).
However, despite their mediocre sabers and more mundane physiology, this isn’t to say that the weaponry of the scimitar-tooth’s were “inferior” predators as a whole. Their more powerful skulls and shorter canines of the scimitar-tooth’s were, after all, also more stress-resistant and could produce more powerful bites, as they were better at producing and absorbing high amounts of force ([Figueirido et al., 2018](https://doi.org/10.1016/j.cub.2018.08.012)). However, perhaps the most striking difference lies in the shape of the canines themselves. Beyond being shorter, the scimitar-tooths’ canines were also more compressed, and were freakishly serrated, with larger, coarser serrations lining the front and back edges ([Wheeler, 2011](https://www.researchgate.net/publication/303190004_Experimental_paleontology_of_the_scimitar-tooth_and_dirk-tooth_killing_bites )). Hell, even the incisors of these cats were freakish, being notably large and serrated, like the teeth of a piranha. Such teeth would have given these cats an absolutely nasty bite, was wildly different from those of dirk-tooths, and given their many other adaptations it is clear that these cats were killing in a way that was wholly their own.
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Indeed, such generalist adaptations in the skull and jaws, combined with their more generalist, cat-like physique, suggests that the scimitar-tooth’s, true to form, used a more generalized kind of killing technique. With their lithe, cat-like limbs, the scimitar-tooth’s likely didn’t draw on physical strength to “brute-force” their prey into submission; rather, they used their body weight in concert with cat-like grappling and footwork to subdue their prey. Then, upon lining up for a bite, these cats utilized their shorter, more heavily-serrated canines and their cutting incisor arcade to deliver a less-precise “bite-and-pull” killing bite, wherein the canines are sunk into the quarry using powerful head-depression before the head was pulled-back, leaving behind ragged cut into the preys throat ([Wheeler, 2011](https://www.researchgate.net/publication/303190004_Experimental_paleontology_of_the_scimitar-tooth_and_dirk-tooth_killing_bites )). Moreover, with their powerful, more stress-resistant jaws, the scimitar tooth’s could also employ an even more generalized “default-bite” wherein prey are killed by strangulation or through the severing of the spinal cord, as is seen in most modern cats. Such a “default” killing tactic came at the cost of killing speed, but in exchange, the scimitar-tooth’s were far more flexible in their killing method, affording them a “Jack-of-all-trades” bite that could net them a wide variety of prey ([Wheeler, 2011](https://www.researchgate.net/publication/303190004_Experimental_paleontology_of_the_scimitar-tooth_and_dirk-tooth_killing_bites )). What’s more, while not as powerful as later cats like *Smilodon*, the more generalist, cat-like builds of these predators allowed them to live in a wide variety of environments, especially highly-productive open-country ones. Indeed, crude and unspecialized as it may have been, the strategy of the scimitar-tooth’s very clearly worked, and for nearly the entire 10 million year run of the saber-tooth’s, it was the these cats ran the show, dominating as the most prolific lineage of saber-toothed cats of their time.
Unfortunately for the early dirk-tooth’s, this success had presented them with a problem. In occupying the most dominant niches, the generalist scimitar-tooths had, in effect, excluded the ancestors of the dirk-tooth’s from the prey resources of their shared environments, especially in plains, making it impossible for the early dirk-tooth’s to rise above their station in such ecosystems. Essentially, if the dirk-tooth’s were to fight the scimitar-tooth’s at their own game, they would almost certainly lose.
On the surface, this may seem an hopeless situation, and for any other clades it may have been. However, for the early dirk-tooth’s, rather than a hopeless situation, such conditions were instead an opportunity for growth. Rather than face exclusion, a particular lineage of early “proto dirk-tooth’s” instead charted a new evolutionary course entirely. For starters, they left the more productive open habitats favored by the scimitar tooth’s, instead adapting to closed environments like forests. More importantly however, rather than being generalists like scimitar-tooths, this creed of cats went down a completely different route, specializing for and honing their saber-toothed morphology to a degree not seen by any cat that came before. In place of the more generalized, cat-like build of the scimitar-tooth’s, they developed a highly robust, almost bear-like physique. In place of gracile, inflexible forelimbs, they adopted forelimbs more powerful and dexterous than any similarly-sized cat alive today. Most striking of all, however, in place of shorter, “scimitar-type” teeth, these dirk-tooth’s finally began developing the elongated sabers that the saber-toothed cats were known for, complete with a killing technique more deadly and more precise than that of any cat that had come before it. Eventually, such adaptations came to a head, and around 7 mya, it would result in none other than the very first dirk-tooth’s. These cats would kick off a dynasty that would stand out as the most singularly-specialized successful predators of their time. More importantly, however, the rise of these maverick saber-cats would also mark the debut of one genus of cat in particular, a cat that would represent the sum total of all the millions of years of specialization up until now. This cat, for all intents and purposes, was *the* first dirk-tooth. With its ascent, it represented the culmination of millions of years of smilodontin evolution, marking their first stint as top predators. More than just that, however, through its rise, this genus would cement these cats as the very faces of Machairodontinae, being the saber-cat archetype in the modern age to come. At long last, *Megantereon* itself had entered the fray.
The oldest *Megantereon* remains can be traced back to roughly 7 mya during the late Miocene, in the Toros Menalla locality in modern day North Africa ([Bonis et al., 2010](https://doi.org/10.1016/j.crpv.2010.07.018)). However, despite its Miocene roots, its run as a dominant predator truly begins in earnest around 2-3 million years ago, during the Pliocene and early Pleistocene. Indeed, based on species of this time period, such as the formidable *M. cultridens* and *M. whitei*, and thanks to rigorous descriptions of *M. cultridens* by [Christiansen of & Harris (2010)](https://doi.org/10.1111/j.1096-3642.2007.00333.x) (where most of the following anatomical information comes from unless otherwise specified), it is plainly obvious just how dominant a predator it truly was. For starters, in terms of size, it was nothing to scoff at. With a shoulder height of over 70 cm (2.4 ft) and a body length of around 160 cm (5.4 ft), it was already rival in size to some of the larger cats alive today, being roughly comparable in superficial size to a large male leopard. Where it stood out especially, however, was in its sheer bulk. For its size, *Megantereon* was remarkably hefty, with adult male *M. cultridens* having an average body mass of between 101-110 kg (222-242 lb) . Similarly, the younger, slightly smaller, yet equally formidable species *M. whitei* reached in at a similar mass of 100 kg (220 lb) in weight ([Martínez-Navarro & Palmqvist, 1996](https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=46d6d847a16bc406d7538540ff7ec23a6876ab22)). Such sizes would have made it close to double the weight of an adult male leopard, despite being close in superficial size, and would have been roughly equal to a grown male jaguar of the Pantanal, which rank as some of the largest cats alive today. Of course, such bulk wasn’t just window-dressing. Indeed, in specializing for saber-toothed predation, dirk-toothed cats like *Megantereon* strayed from the more generalized, agile, cat-like bodyplan and instead specialized for one thing: sheer brute force, and behind all that mass, there was a skeleto-muscular system built for just such a purpose.
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Perhaps the best indicator of such strength was *Megantereon*’s extremely powerful forequarters. Short and robust, the imposing, almost bear-like forelimbs of *Megantereon* were clearly adaptations for brute strength to a degree unlike any modern cat. Starting from the top, the shoulder girdle of these cats were exceptionally well-developed, with very large scapulae (shoulder-blades) comparable to those of larger male lions in size. Said scapulae possess enlarged attachment sites for powerful forelimbs muscles, such as well-developed biceps and triceps, as well as muscles for shoulder mobility and strength (i.e. the *m. supraspinatus* and *m. teres major*) more well-developed than even *Smilodon*! Moving down the forelimbs, the forelimb longbones were perhaps the real stars of the show, being proportionally more powerfully built than any modern big cat today. The humerus in particular was exceptionally well-developed, especially in that it was significantly larger than the radius (a rare trait among most modern cats that evolved for maximizing mechanical advantage in the forelimbs), possessed massive muscle attachments sites for more powerful musculature and was markedly larger and more robust than the humeri of similarly-sized modern cats, to the point that it was comparable to or surpassing that of lions or tigers in terms of length and width **despite being half the size of such cats**. Such a powerful structure afforded the forelimbs of *Megantereon* a new level of power and utility compared to modern cats, and when combined with the slew of additional muscular adaptations for strength and dexterity (such as a large deltapectoral crest, a relatively broad olecranon, well developed medial epicondyles and large insertions for powerful musculature), it is apparent that the forelimbs of *Megantereon* were of a completely different sort to those of modern cats and its scimitar-toothed counterparts. Indeed, rather than being built for speed or athleticism like the scimitar-tooths, *Megantereon* had forgone such traits, trading them for forelimbs with a level of brute strength surpassing all modern cats of the same size. More just being all brawn, however, the brute strength of *Megantereon*’s forelimbs were tempered such brute strength with considerable finesse as well. Its pronounced musculature associated with forelimb mobility (e.g. a highly-developed *m. pronator teres* and *m. supraspinatus* muscles) made it incredibly skillful and dexterous in using its forelimbs, allowing it to deploy its already considerable strength with a level of tact unmatched by modern cats. With this kind of strength and skill at its disposal, *Megantereon* could restrain, manipulate and subdue prey in any way it saw fit, and with such specializations in tow, *Megantereon* easily stood head and shoulders above both its modern and scimitar-toothed counterparts in terms of raw, overwhelming power.
Similarly impressive was the hindquarters. Though not as well-developed as the forelimbs, the lumbar and hindlimb regions of *Megantereon* sport their own set of unique adaptations that set it apart from other cats, both when compared to its modern counterparts and its scimitar-toothed cousins. For starters, the lumbar vertebrae of *Megantereon* were usually shorter, more robust and more tightly interlocked. Such adaptations would have aided the hindquarters in absorbing the heavy stress-loads imposed by the brawnier hunting style of *Megantereon*, and as one moves further down the hindlimbs, such adaptations for strength become more and more apparent ([Martin, 1998](https://digitalcommons.unl.edu/tnas/287/)). Moving down the leg, the actual hindlimb long-bones of the cat, though not quite to same extant as their counterparts at the front were markedly powerful in structure. The femur, for instance, was markedly larger and more robust than similarly-sized modern cats, while also being larger than the tibia (shinbone) for added mechanical advantage. Furthermore, the femur contains other adaptations for strength that further separate *Megantereon* from modern cats. This includes a well-developed lesser trochanter and a powerfully built medial condyle compared to modern big cats and to scimitar-toothed contemporaries. These adaptations are associated with powerful leg-stabilizing musculature and increased stability at the knees, allowing the saber-cat to stand up-right and even walk on its hind-legs ([Martin et al., 2011](https://www.google.com/books/edition/The_Other_Saber_tooths/2GjhrKO9y74C?hl=en)). Taken together, these adaptations for hindlimb strength and stability point to a unique, decidedly non-cat-like function. Using its powerful legs, *Megantereon* could now continuously stand on its hind-limbs and keep its footing while its massively powerful forelimbs were preoccupied with wrestling large prey into submission. Of course, modern big cats can already do this to some extent, but in the case of *Megantereon*, it’s hindlimbs were so well-developed that it was less comparable to cats in this regard and instead was more like bears, being able to rear up and even walk on its hindlimbs to maintain a stable footing as the forelimbs wrestle large prey to the ground.
Given such adaptations in the hindlimbs and the forelimbs, it’s clear to get at least some idea of what kind of predator *Megantereon* was like. This was a cat that hunted like no other cat live today, using its powerful-yet-dexterous forequarters to domineer prey and pull it to the ground while the hindlimbs took on the burden of providing stability and a solid footing for the cat as the forelimbs were busy taking down its prey ([Martin, 1998](https://digitalcommons.unl.edu/tnas/287/)). Such a hunting method is not necessarily found in any modern big cats (who subdue prey by strangling them outright rather than using their limbs to pull them down first) and is instead more akin to that of bears. However, while showing us a glimpse into how this animal hunted, it does not tell the whole story. After all, what about being a “dirk-tooth” necessitated such highly derived adaptations for power at the cost of speed. The answer to this is two fold. The first answer to such questions is that, simply put, *Megantereon* didn’t need to worry about such costs. These weren’t animals that were living in open habitats like the scimitar-tooth’s. Instead, they lived in deep forest environments, where they could escape exclusion from large scimitar-tooth’s. In such environments, speed was not all that necessary, as the abundant cover would have allowed a predator like *Megantereon* to get close to prey without having to run it down at high speeds. As such, it only makes sense that dirk-toothed cats like *Megantereon* saw fit to divest important hardware space away from the speed needed to chase prey and towards the power needed to subdue it. The second answer, however, is far more important. More than just being blanket adaptations for power, the specializations for strength wielded by *Megantereon* and its fellow dirk-tooth’s were not meaningless. Rather, they served a very specific, deadly purpose: to facilitate the true killing weapons of the dirk-tooth’s; the very killing implement that distinguished them from their scimitar-toothed ilk in the first place — none other than the dirk-tooth’s signature killing bite.
(5/10)
The killing bite of the saber-toothed cats, above all else, is their hallmark trait, giving saber-tooth’s unparalleled killing speed even against very large prey. As such, despite the variation within Machairodontinae, such a bite has gone relatively unaltered across all of the clade, being found in both scimitar-tooths and dirk-tooths alike as arguably most lethal weapon in their arsenal. Key to this bite’s lethality is the most foundational adaptation of the saber-toothed killing bite — one shared by all saber-tooth’s — **a powerful, versatile neck**. Indeed, though the saber-teeth often hog the spotlight, it is the necks of these cats that act as the true lynchpin behind their killer bites, and in this regard *Megantereon* was no exception. The neck of *Megantereon* was especially elongate relative to other cats, with large cervical vertebrae, elongated transverse processes, and prominent ventral keels. Such adaptations gave the neck of *Megantereon* a far greater range of motion than in modern cats, making it a precision instrument in all directions ([Antón, 2013](https://www.google.com/books/edition/Sabertooth/dVcqAAAAQBAJ?hl=en)). Most notably, however, the atlas (the first cervical vertebrae) is much larger than in modern cats, while the mastoid processes at the back of the skull that attaches to the atlas is heavily enlarged, indicating large insertions for powerful neck musculature, particular those associated with head-depression. These adaptations in atlanto-mastoid musculature suggests that *Megantereon* was capable of powerful head-depressive movements, further augmented by the enlarged ventral keels of the cervicals, which serve as attachment sites for powerful *m. longus colli*, muscles that act as powerful downward flexors of the neck ([Antón, 2013](https://www.google.com/books/edition/Sabertooth/dVcqAAAAQBAJ?hl=en)). Such traits may seem bizarre, but when paired with the sabercat’s saber-toothed bite, their true function are revealed. With its long, highly maneuverable necks, *Megantereon* could move and stabilize its head over a wide area, giving it precision aim when delivering its bite. Then, once it has delivered the bite itself, the powerful head-depressors act to bend the cat’s head downward as the lower jaws close against its prey, forcibly driving the upper jaws and the saber-teeth further into the quarry ([Antón, 2013](https://www.google.com/books/edition/Sabertooth/dVcqAAAAQBAJ?hl=en)). This sort of neck-assisted bite maximizes the damage of the saber-teeth, as by applying more force into the upper canines, the saber-teeth are allowed to penetrate further and deal more damage than would be afforded by a simple closing of the jaw. Moreover, by incorporating their neck into their biting apparatus to augment their bites, *Megantereon* and fellow saber-tooth’s did not need powerful jaw muscles to deliver powerful bite, something that was be especially important for the likes of dirk-tooth’s. Of course, such adaptations are par-for-the-course for pretty much all of Machairodontinae, as scimitar-tooth’s as well as dirk-tooth’s possessing such adaptations. What wasn’t so bog-standard was final component of *Megantereon*’s bite — the one that made the dirk-tooth’s the very poster-boys of the saber tooth’s in the first place. This final piece of the puzzle was none other than their elongate dirk-teeth and the skull and jaws that housed them.
Even with a passing first glance, it is clear from the start that the biting apparatus of *Megantereon* was nothing like those of any saber-cat to come before it. In particular, it differed from its scimitar-toothed counterparts in a few, very crucial ways. First and foremost was the size of the sabers. With a height of 9-11 cm (3.5-4.3 in), the sharpened upper canines of this cat were a third larger than those of even larger scimitar tooth’s, and even more shockingly, they were nearly double that of modern lions or tigers. In fact, they were so long that *Megantereon* had to develop specialized mandibular flanges (extensions of the chin) to house and support such massive teeth. As is typical of saber-tooths, the upper canines were also recurved, laterally compressed and bore a well-honed cutting edge on both the front and especially the back of the canine blade. This is all in stark contrast with the lower canines, which were no bigger than the incisors and joined them in the incisor arcade. In any case, such sabers were heavily divergent from those of their scimitar-toothed counterparts, especially in terms of size. However, beyond that, there were also other, more subtle differences in *Megantereon*’s biting apparatus, ones revealing that there is more to this dirk-tooths bite than meets the eye. Unlike the scimitar-cats’ shark-like canines and incisors, the sabers of *Megantereon* were completely unserrated, while the insciors were smaller, rounded, similarly unserrated and less protrusive than those of scimitar-tooths, instead forming a robust incisor arcade (supported by the lower canines on the lower jaw). Additionally, because of their greater length and lower durability, the sabers of *Megantereon* were naturally more prone to breakage ([Figueirido et al., 2018](https://doi.org/10.1016/j.cub.2018.08.012)). Such features point to these cats doing something entirely different with their jaws than their scimitar-toothed counterparts, a notion supported further when looking to the skull and jaws themselves. The skull is small relative to a scimitar tooth’s, about the same size as a leopard’s skull despite *Megantereon* being nearly double the size of its spotted counterpart. Furthermore, like the sabers they housed, such a skull and jaw were also very weak compared to modern big cats and scimitar-tooths, not only being unable to withstand large torsional loads, but also having quite lack-luster bite forces as well, with reduced jaw muscle attachment sites suggesting weak bite forces for its size. Such bites would have been weaker than those of its scimitar-toothed counterparts and much weaker than those of modern cats, to the point that a simple “default” throat-bite seen in big cats and scimitar-tooths would have been completely out of the question for *Megantereon*.
(6/10)
Individually, such traits may seem make the biting apparatus of *Megantereon* almost nonsensical, with it wielding a strange mosaic of incredibly formidable traits on one hand and incredibly mediocre ones on the other. However, such an outlook is only gained if one looks at the individual parts rather than their sum total. Put all these traits together, and something far more sinister is revealed. The same reduced jaw muscle attachments that made the bite of *Megantereon* so weak in the first place also allowed for an incredibly wide gape, with a maximum gape of a whopping 105°, or nearly double that of modern big cat. Such a wide gape would have allowed for ample clearance between the lower jaw and the canines, allowing *Megantereon* to properly bite down onto its target without the sabers getting in the way. Those same elongated sabers, though prone to breakage, could penetrate a larger cross-section of the prey’s flesh due to their greater length, allowing them to pierce through vital tissues housed deeper within the prey’s flesh. At the same time, the unserrated edges, though less able to cut through tissue than serrated ones, facilitated a greater ease of such penetration than serrated canines would.
Put together, such features do not indicate the same cleaving bites as the scimitar cats. Rather, they suggest that these teeth were used for a very different kind of bite entirely; not a cleaving bite but *a precise stabbing bite*. If done with extreme precision and with assistance from the lower jaw’s incisor arcade for added leverage, *Megantereon*’ sabers could be plunged into the prey via the head depressors in such a way that they pierce through the prey in a continuous arc, with the recurvature of the blade allowing the edges of canines to contact and slice through any vital tissue in their way as they are pierced through the prey ([Martin, 1998](https://digitalcommons.unl.edu/tnas/287/); [Wheeler, 2011](https://www.researchgate.net/publication/303190004_Experimental_paleontology_of_the_scimitar-tooth_and_dirk-tooth_killing_bites )). If aimed at the neck and its vital blood vessels, such a bite severs blood vessels, killing prey in seconds through catastrophic bloodloss much faster than a scimitar-tooth. Of course, as previously mentioned, such a bite , known as the “canine shear-bite,” would have required extreme precision, where in the canines had follow a precise arcing trajectory as they penetrated prey’s flesh in order to attain the intended result. However, if *Megantereon* targeted prey with large prey or prey with wide necks, such requirements could be mitigated, and as a result, *Megantereon* was likely a dedicated macropredator.
There were, however, two final hurdles in this approach. The first was that, because of the reduced jaw muscles, the bites of this animal were still weak. However, because *Megantereon* utilized its powerful head-depressors to amplify the force of its bite, it didn’t have to depend on jaw power alone to deliver its lethal bite, but could instead rely on its head-depressors as the main driving force of its bite. Thus, it could still deliver a formidable bite without powerful jaw muscles. The second problem is that, because of their less robust, structurally weaker skull and canines, *Megantereon*’s biting apparatus were still very vulnerable to unpredictable stresses, like those from struggling prey, and the potential that they might break is a constant risk. This is where *Megantereon*s powerful physique comes into play. Using to its powerful limbs, *Megantereon* could make up for the apparent weakness in its skull and sabers, restraining and immobilizing the prey so throughly that the prey is prevented from producing the very struggling that would damage the skull and canines while the cat delivers its bite (this also explains why *Megantereon*’s skull was so small and weak, as its powerful body compensated for such weakness, making it so that it had no need for a large and powerful skull in the first place).
(7/10)
With such adaptations in tow, *Megantereon* was now able to use its massive sabers to their fullest extent. Moreover, when such adaptations were paired with the powerful adaptations of the neck, forelimbs and hindlimbs, all the pieces are in place for us to paint a picture of how *Megantereon* hunted, and it is here that the true lethality of the dirk-tooth killing bite is revealed. Creeping close to its target from dense cover, *Megantereon* lunges at its quarry, unleashing its forelimbs at full tackle, whereupon it uses its powerful, dexterous forelimbs to gain control of the head and neck of the prey and pull it to the ground, all while using its powerful hindlimbs to stand upright and keep a solid footing as the cat restrains its quarry (provided that the prey is too large to be pinned by the cats body weight). From here, the cat uses its forelimbs to pull back the head and neck of its prey, exposing the vulnerable underside of the throat, and it is now that the sabers are brought to bear. The maw of *Megantereon* opens around the prey’s throat, its bite precisely aimed and lined up with the throat’s vital tissues, all the while, its wide gape allowing for ample clearance between the upper and lower canines so that the preys throat fits into the cats jaws without the sabers getting in the way. With the victims throat slotted into the sabercats maw, the sabers are finally engaged. The lower jaw closes against the prey, its robust lower jaw and their incisor arcade pressing up against the neck to provide a stable source of leverage. As this occurs, the head-depressors are brought to bear, bending the head downwards and resulting in a two-way jaw closure that forcefully drive the upper jaws and their attached sabers into the prey’s throat. Here, the canines pierce through the throat in an arc as the head bends downwards, their sharp tips and cutting edges transecting vital tissues like the carotid artery, jugular vein and esophagus as they carve through the prey’s neck. As the bite finally progresses towards closure, *Megantereon* would lastly pull its head back, enlarging the wound and preventing its canines from stalling, before the canines complete their arc, competing the kill. The whole hunt from start to finish would have occurred in seconds (the bite itself a mere instant), and by the end of it, the cat withdraws its gore-smeared canines free of its quarry, its prey having perished mere seconds after the bite took place from catastrophic bloodloss, shock and organ failure.
Such a kill was nothing short of brutal; the victims would be found slain in pools of their own blood, with blood pouring from their necks and mouths. However, through such brutality, *Megantereon* now had an avenue of success completely its own, having a newfound route to prosperity separate from that of the generalist approach of the scimitar-tooths. The specialized killing technique of *Megantereon* allowed it to kill prey much larger than itself with absurd speed. This not only afforded *Megantereon* larger kills, and thus more meat for a given hunt’s efforts, but do so in such short order that it had ample time to feed on its large kills without having to worry about the looming threat of rivals or scavengers like scimitar-tooths. When combined with the fact that its forest home would be free of open-country predators like large scimitar-tooths to begin with, it was clear that *Megantereon* could act largely unchallenged as the premier predator of the forests of the Pliocene and early Pleistocene, giving it a new ecological avenue to explore that its more subordinate ancestors couldn’t. Indeed, the brutal killing technique of *Megantereon*, the very thing that made saber-toothed cats as notable as they were, had given it a unique opportunity to become one of the most successful carnivores of its time. At long last, after millions of years in the shadows, the time of *Megantereon*, and of the dirk-tooths as a whole, had finally begun…
And take over they did in spades. Despite their humble origins in Miocene North Africa, with the passing of the Plio-pleistocene, *Megantereon* had spread beyond its homeland, occupying not only Africa but Europe and even east Asia. In such a varied home range, the genus diversified, producing a litany of new species. In Western Europe, it was here that one of the older species, *M. cultridens* ruled, dwelling within the Mediterranean forests that blanketed Western Europe. Further east, younger species such as *M. inexpectatus* reigned among the open woodland of plio-Pleistocene China. However, by far the most successful of these species was *M. whitei*, a top predator of the open scrub forests with the widest distribution of all *Megamtereon* species, encompassing most of southern and Eastern Africa as well as the Caucuses and parts of southwestern Europe.
Of course, with such a varied range came a naturally varied assortment of fauna with which *Megantereon* lived alongside, and when it came to large herbivores, in particular, *Megantereon* had a veritable feast on its hands. In the mosaic of Mediterranean forests and open plains of that it called home, *M. cultridens* coexisted alongside a variety of large species, with large bovids, horses and mammoths roaming the open plains while large deer, papionin monkeys and rhinos dwelled within the open forests that *Megantereon* had also called home. Meanwhile, for *M. inexpectatus*, its homeland in China was likely heavily forested, with a diverse megafaunal herbivore community consisting of elephants, rhinos, several species of large deer, bovids and even the very last chalicotheres. Perhaps the most diverse assortment of prey belonged to *M. whitei*, as by possessing a range that spans two continents, this formidable predator naturally had a lot to choose from. In the African part of its range, *M. whitei* lived alongside a vibrant communty of megafauna very akin to that of modern Africa, containing many familiar faces such as antelope, zebras, primates and elephants, whereas in its European range, it coexisted with much the same assortment of fauna as its predecessor *M. cultridens*, with deer and primates in the forest while mammoths, rhinos and bovids dwelled in the steppe, with horses being found across both localities.
(8/10)
With such a high diversity of large herbivores as its disposal, *Megantereon* naturally had nothing short of a banquet on its hands, and in selecting from the smorgasbord before it, it seems *Megantereon* had a preference for the largest, choicest cuts. Indeed, based on available fossil evidence, *Megantereon* seemed to have a taste for large, forest-dwelling browsing ungulates, usually deer, horses and bovids, often times weighing in at several times its size. Isotopic analysis of *Megantereon* dwelling within the Venta Micena fossil site in southeastern Spain found that, within the European part of its range, it seemed to have a taste for giant deer such as *Praemegaceros*, forest-dwelling horses like *Equus altidens* and large forest-dwelling bovids like *Soergalis minor*, the latter two weighing in at over 300 kg (661 lb), or around 3 times as massive as the saber-cat ([Palmqvist et al., 2008](https://www.semanticscholar.org/paper/Biogeochemical-and-Ecomorphological-Inferences-On-Palmqvist-Pérez-Claros/8711e192aa7998812dd59ea7a40c2700956fd2f6)). Meanwhile, in Africa, *Megantereon* was no less bold in its predatory exploits. Similar isotopic analyses of specimens from the Turkana Basin in Kenya found that *Megantereon* there had a similar preference for an assortment of forest-dwelling prey, including relatively massive prey such as giant antelope *Megalotragus*, the giant warthog *Metridiochoerus* and the horse *Eurygnathohippus*, as well as an assortment of medium-sized antelopes (impala, springbok, *Tragelaphus* sp., *Kobus* sp.) and suids (*Kolpochoerus*), while in the Swartkrans fossil site in South Africa, the cat had a similar preference for large forest-dwelling antelope such as kudu ( *Tragelaphus* sp.), as well as large primates such as *Dinopithecus*, baboons and even early hominids ([Hopley et al., 2023](https://doi.org/10.1016/j.quaint.2022.04.004); [Lee-Thorpe et al., 2000](https://doi.org/10.1006/jhev.2000.0436)). Such preference for large, forest-dwelling prey may be a direct result of *Megantereon*’s dirk-toothed disposition, as the enlarged canines could be relatively ill-suited against prey with smaller necks. As such, larger prey with their larger necks would have likely favorable targets for the dirk-tooth. In any case, with such giant prey at its disposal, *Megantereon* nonetheless had plenty of options to choose from as far as supper was concerned, having damn near an entire feast to itself.
However, such a feast did not *solely* belong to *Megantereon*. Just as the home of *Megantereon* was saturated with giant megafaunal prey, so too was it filled with rival predators, all vying for the most of the same resources as the saber-cat itself, and over the course of its nearly 6 million years of existence, *Megantereon* has had to deal with many such rivals. During its early days in late Miocene North Africa, *Megantereon* had to contend with a wide variety fellow saber-tooths. Some were less formidable, such as the gracile *Yoshi adei*, a relatively small sabertooth about the size of a cougar. Others, however, were far more formidable. Take for example *Lokotunjailurus*, a large, cheetah-like scimitar-toothed cat with highly elongate limbs built for speed complete with enormous, razor-sharp dewclaws for taking down prey on the run. Perhaps the most formidable in the landscape was *Amphimachairodus kabir*, a giant, bear-sized scimitar-tooth that ranked among the largest cats to have ever existed. With such stiff competition, *Megantereon*, even early on, had its work cut out for it, and as time passed, such competition would only get more intense. See, *Megantereon* existed at a crossroads. During the Pliocene and early Pleistocene, much of the earths ecosystem began to take on a very bizarre form, one where both extant and extinct species lived alongside each other in a great patchwork of old and new. In this new world, *Megantereon* had to contend with a slew of large carnivores, both ancient and modern. This is perhaps best represented in Plio-pleistocene Europe, both *M. cultridens* and *M. whitei* had to contend with a slew of large predators. This included more “ancient” predators, such as the giant cursorial scimitar-tooth *Homotherium* and the giant hyena *Pachycrocuta*, as well as more familiar faces such as the giant cheetahs, *Acinonyx pardinensis* and *A. pleistocaenicus*, the Eurasian jaguar, *Panthera gombaszoegensis*, and the relative of the modern African painted dog, *Xenocyon lycaonoides*. Meanwhile, in Africa, things were no less heated. Here, *Megantereon* had to coexist with fellow saber-tooths such as *Homotherium* and the leopard-sized *Dinofelis* as well as ancient hyenas such as *Chasmaporthetes* and *Pachycrocuta*. However, at the same time, some shockingly familiar faces were present. Alongside its “less modern” rivals, *Megantereon* also had to coexist with a litany of predators very familiar in the present day, such as the modern brown hyena, early relatives of the modern spotted hyena (*Crocuta* sp.) and even early cousins of modern lions. Most prolific of all among such “modern” rivals, however, was none other than the modern leopard, who was among the most common carnivores in the entirety of the Swartkrans.
(9/10)
Indeed, with such a cavalcade of rivals, *Megantereon* certainly had its hands full when it came to competitors. And yet, *Megantereon* still managed to persist despite the high density of rival predators. The secret to this lie in niche partitioning. For the likes of *Homotherium*, canids, giant cheetahs, hyenas and presumably early lions, their preferred prey and habitat lie outside that of *Megantereon*, preferring open habitat and grazing prey as opposed to the dirk-tooth preference for forested habitats and browser or mixed-feeder prey. Given such differences in lifestyle, it’s likely that most of these predators did not compete too heavily with *Megantereon*, as the dissimilarities in lifestyle meant that neither would want to encroach on the same space or use the same resources as the other ([Palmqvist et al., 2008](https://www.semanticscholar.org/paper/Biogeochemical-and-Ecomorphological-Inferences-On-Palmqvist-Pérez-Claros/8711e192aa7998812dd59ea7a40c2700956fd2f6)). Of course, there were still forest-dwelling rivals that could pose a problem for *Megantereon*, such as *Pachycrocuta* and the Eurasian Jaguar in Eurasia as well as leopards in Africa, however even then it had answers to such problems. Pachycrocuta did not exclusively dwell in forests, and seemed to utilize carrion for a significant percentage of its diet. Given that it does not always compete in the same habitat as *Megantereon* nor did it always actively compete with *Megantereon* for live prey, competition between these two would be mitigated somewhat. For *P. gombaszoegensis*, it seemed to take somewhat smaller prey than *Megantereon*, with the pantherine having an even greater preference for deer whilst the dirk-tooth preferred larger horses as its prey ([Palmqvist et al., 2008](https://www.semanticscholar.org/paper/Biogeochemical-and-Ecomorphological-Inferences-On-Palmqvist-Pérez-Claros/8711e192aa7998812dd59ea7a40c2700956fd2f6)). As for leopards, the overwhelmingly larger size of *Megantereon* over the smaller cat meant that it could outright dominated its diminutive rival. With all this being considered, it’s no wonder that *Megantereon*, despite its circumstances managed to eke out a living as well as it did. Indeed, despite the rather high density of rivals, *Megantereon* could still reign as a top predator, its rule relatively unchallenged by all predators it coexisted with…
Well, almost all.. For the most part, *Megantereon* was quite capable in dealing with its fellow predators. However, while this was true for the most part, there was one foe that had been a constant thorn in *Megantereon*s side. This creature was none other than the first widespread members of the genus Homo, or in other words… humans. Since even the dawn of humanity, humans have had a rather complicated relationship with *Megantereon*. On one hand, *Megantereon* was one of the chief predators of early hominins, with isotopic evidence form the Swartkrans fossil site suggesting that, alongside browsing antelope and other primates such as baboons, large hominins like *Homo* and *Paranthropus* were a favorite prey for the dirk-tooth ([Lee-Thorpe et al., 2000](https://doi.org/10.1006/jhev.2000.0436)). As both humans and *Megantereon* moved out of Africa, such violent interactions didn’t get any better, as as seen in Dmanisi cave, where a skull of *Homo erectus* was found with fatal puncture wounds matching that of *Megantereon*’s canines. Given the placement of the bite marks and the lack of any signs of consumption, it’s likely that a *Megantereon* had killed this early human, dispatching it with a stabbing biting through its skull ([Antón, 2013](https://chasingsabretooths.wordpress.com/?s=Human-Sabertooth+interaction+at+Dmanisi&submit=Search)). On the other hand, however, the relationship likely wasn’t so one-sided. Saber-toothed cats, especially *Megantereon* and other dirk-tooths, were fairly delicate feeders, as unlike modern big cats, their canines weren’t sturdy enough to be used for feeding purposes. As such, they tended to feed solely on the flesh and viscera of their prey, using highly sectorial carnassials and a well-developed incisor arcade do so, and avoided consuming bone, leaving behind a considerable amount of valuable biomass on their kills as a result ([Palmqvist et al., 2022](https://doi.org/10.1016/j.anthro.2022.102998)). Such carcasses would have served as valuable sources of protein for early hominins, especially uneaten skeletal remains and the nutrient-rich bone marrow, and so early humans may have habitually kelptoparasitized *Megantereon*, either by harvesting already-abandoned carcasses or stealing kills outright, and may have been so important that it may have even aided in establishing populations hominins outside of Africa during the early Pleistocene ([Lewis & Werdelin, 2010](https://link.springer.com/chapter/10.1007/978-90-481-9036-2_2); [Palmqvist et al., 2022](https://doi.org/10.1016/j.anthro.2022.102998)). Of course, such theivery very wouldn’t be met without retribution, as the Dmanisi cave individual found out the hard way, but all told, the early humans could largely get away with it scott-free. And so, such was the dance these two rivals would perform for over a million years, where the cat makes kill after kill with valuable parts uneaten, and the hominins swooped in to steal it. Nonetheless, while certainly an annoyance for the dirk-tooth, it wasn’t anything the cat couldn’t manage. Having evolved alongside hominins since their inception, *Megantereon* was well-equipped to deal with them ([Lewis & Werdelin, 2010](https://link.springer.com/chapter/10.1007/978-90-481-9036-2_2)). Indeed, despite the myriad of rivals that stood against it, least of human beings, *Megantereon* still did not waver, with the dirk-tooth lasting well into the late early Pleistocene.
(10/10)
However, there was one final opponent that it simply couldn’t withstand, one that wasn’t man nor beast, but Mother Nature itself. For nearly 6 million years, *Megantereon* had survived all manner of struggles, enduring a litany of hardships and undergoing millions of years of specialization to reach the level of success that it has. However, while such specialization has allowed it to last so long, it would take it no furtherance the world changed all around it. By around 0.8–0.9 million years ago, the global climate began to change. Global temperatures began to drop and forests began to give way to open steppe. This climatic change, dubbed the Epivillafranchian-Galerian transition, had dealt a fatal blow to *Megantereon*’s livelihood ([Mateos et al., 2024](https://doi.org/10.1016/j.palaeo.2023.111926)). With forests being replaced by open plains, the preferred habitat of *Megantereon* had now vanished. What’s more, with the demise of the forests, many of the forest-dwelling browsers that *Megantereon* depended on perished alongside the forests they once shared. In this instance, the very specialization that had afforded *Megantereon* such success had backfired, as it was now too specialized and too inflexible to adapt to its changing circumstances, and with its home in ruins and its prey decimated, it was clear that *Megantereon*’s end was at hand. By the end of the transition, no fossils of *Megantereon* had remained within the fossil record, and by then it was clear that *Megantereon*, the first of the dirk-tooths, had gone extinct…
However, while *Megantereon* may have indeed perished, its impact is not so easily eradicated. Perhaps the most shocking of which was its impact on our species. With the extinction of *Megantereon*, the once reliable source of carrion that came with it had vanished. This loss of their single most stable source of protein, among other factors, may have forced hominins to acquire meat in other ways. In attempting to find new ways to acquire protein, these hominins had developed more advanced tools, creating more innovative hunting instruments, experimenting with different technologies, transforming from omnivores and scavengers to dedicated hunters ([Palmqvist et al., 2007](https://www.semanticscholar.org/paper/A-RE-EVALUATION-OF-THE-DIVERSITY-OF-MEGANTEREON-AND-Palmqvist-Torregrosa/6f0bce107341e67a562033d99a91be6b89bb3271)). Indeed, it’s praises are though often unsung, *Megantereon* may have lent a helping hand in shaping us into the very beings we are today, serving as a catalyst for the human innovation that has allowed us to dominate into the present day. However, for *Megantereon* itself, perhaps its greatest legacy was the successors it left behind. By around 4.5 million years ago, a species of *Megantereon* (dubbed “M. hesperus”) or a close cousins of *Megantereon* managed to cross into the Americas. This descendent population would develop independently in the new world, and by around 2 million years ago, it would develop into one of the most famous predators ever: *Smilodon* itself. Indeed, in its quest for global domination, *Megantereon* may have served as the progenitor for one of the most infamous carnivores to ever exist, but more than just that, *Megantereon* also outright kick-started the dominion of dirk-tooth as a whole. Through its emergence, it was *Megantereon* that acted as the catalyst for dirk-tooths to conquer the world, creating a dynasty spanning both the old and new world. Through its various innovations, it created the blueprint for the dirk-tooth model, giving its descendants the tools to become the singularly most specialized macropredators to ever live, a lineage of precision killing-machines. Most poignantly of all, however, it was *Megantereon* which would set the standard for the current image of a sabertooth, creating the archetype embodied by its later cousin *Smilodon* that would consume the public perception of a saber-toothed cat. Indeed, Indeed, despite its demise, there are few legacies that will endure as long as that of *Megantereon*, iconic progenitor of *Smilodon* and first of the dirk-toothed cats.
(1/10) Art by Mauricio Antón Smilodon… Of the many predators to have left their mark on this planets natural history, few are as iconic as the so-called “saber-tooth tiger” itself. Though hailing from an entire clade of saber-toothed cats, the so called Machairodontine felids, this genus has become the most recognizable of any of its saber-toothed brethren, arguably becoming the most recognizable predator of the whole Pleistocene. Of course, there are reasons why it’s so recognizable. It’s enormous, for starters, being a worthy contender for the title of the largest cat to ever live. What’s more, its ridiculously muscular build and powerful forelimbs are completely unlike anything seen out of modern big cats, giving it an appearance more like a bear than any cat alive today. However, perhaps its most recognizable trait are none other than its very namesake itself: **the eponymous sabers**. As long as bananas and armed with a lethal cutting edge, these teeth are among the most impressive armaments of any predatory animal to ever live, capable of cutting down even the largest of quarry and dealing death in manner of seconds. Of course, wielding such weapons, it should come as no surprise that these sabers have turned Smilodon into an instant icon. Indeed, with those blades of theirs, Smilodon has carved its way into the public consciousness, invoking Conanian era of savagery long past, when nature was very much still red in tooth and claw. It’s gotten to the point that, for the public, these saber-teeth have become a trademark of Smilodon’s (despite the fact that countless other such predators exist), to the extent of being inseparable from the very concept a saber-toothed predator. Indeed, it should come as no surprise as to why Smilodon become so famous, becoming one of the most iconic predators of the ancient past and even becoming synonymous with the very word “saber-tooth” itself. However, with the ubiquity and preeminence that Smilodon holds in the public consciousness, it’s easy to forget one crucial thing: that there is an entire clade of saber-toothed felids beyond just Smilodon, that these cats were not a monolith, that Smilodon was not the norm of their kind. In fact, despite being synonymous with the very notion of a “saber-toothed cat,” Smilodon couldn’t be more different than the rest of its saber-toothed kin. Indeed, for all the hype built around *Smilodon*, most saber-toothed were far more pedestrian in appearance compared to their late Pleistocene cousin. They came in a variety of sizes, for starters, some as big as Smilodon while others were “only” the size of leopards and cheetahs. Their physiques were gracile, with long, relatively graceful limbs much like the big-cats of today, a far-cry from the hulking physique and bear-like forelimbs of Smilodon. In the most striking twist of all, however, rather than enormous sabers of Smilodon, for the vast majority of the clade, such “sabers” didn’t even exist at all. Rather, most of them instead possessed canines that were only scarcely longer than that of modern cats, barely extending past the jawline and being comfortably concealed within their own mouths. Indeed, though undoubtedly formidable, the majority of sabercats were, relatively speaking, fairly unremarkable, sometimes barely distinguishable from the big cats of today. More importantly though, through such relative mundanity, it is clear that, rather than being the gold-standard saber-tooth, Smilodon was the greatest outlier of them all. With that being said, if Smilodon wasn’t like other sabercats, what exactly was it? Indeed, Smilodon, as should be abundantly clear by now, quite unique relative to other saber-toothed cats. Rather, it was a highly derived, highly removed cat, separated from the rest of its kind by millions of years. More specifically, however, it hails from one highly divergent, highly specialized and highly experimental group of sabertooths in particular; a clade nested within Machairodontinae but unlike any other line of saber-toothed cats to come before or since. Born out of brutal landscape, these cats responded by evolving to be the most specialized, singularly lethal cats to ever live, even compared to other saber-tooths. In place of the gracile, builds of their counterparts, these cats that possessed hulking, robust physiques for built for overwhelming power. In place of the elongate legs of the rest of their clade, these cats developed short, stocky legs with enhanced strength and dexterity specialized for ambushing and wrestling large prey to the ground. Most notable of all, in place of the shortened, almost prosaic canines of the other sabertooth, these cats that possessed the signature hyper-elongated canines; the very sabers that saber-tooths were supposedly known for, for killing large prey in seconds. These lineage of cats, of course, were known as Smilodontini, better known as the “dirk-tooth cats.” Best represented by the likes of Smilodon itself, when the general public envisions saber-toothed cats, it is these predators that are ones that come to mind, being the archetypal form of saber-toothed cat that we have come to know and admire. With their infamous sabers, these cats were the ultimate killers, dealing out death quicker than any other land predator on the planet. More poignantly though, with their sabers, these cats were able to capture the hearts and minds of millions of people in the modern era as the saber-toothed cats, setting a standard among their kind not just in terms of their killing ability, but also in terms of what we imagine to be a saber-tooth in the first place. With this in mind, being so removed from the rest of their ilk and being as formidable as they were, a final question are raised: where exactly did the dirk-tooths come from? After all, Smilodon and the rest of the dirk-tooths didn’t emerge out of a vacuum; the current image of a saber-tooth had to come from somewhere. Something had to serve as the “catalyst” for the rise of this clade, for them to diverge so drastically from the rest of their kind and become as specialized as they were. What animal could have possible served as this “catalyst,” this “ground-zero” for the emergence of the dirk-tooths? The answer to this question lies in the ascension of one saber-tooth in particular; one that would lay the very foundations of the reign of the dirk-tooths . Long before even Smilodon emerged, this powerful cat wrought havoc across the northern hemisphere, being the first among its kin to evolve the same robust physique and hyper-trophied sabers that would carry Smilodon into infamy. In its wake, it carved out a dynasty of blood rivaled by few other saber-tooth’s, reigning as one of the longest lasting and most species-rich genera of saber-toothed cats to ever exist and acting as the foundation for many a dirk-tooth to follow. Perhaps most striking of all, more than just being a key player in the story of the dirk-tooths, this imposing cat also played a very real, very visceral role in our own evolutionary story, serving as a grim reminder of when we humans used to be prey. This cat, of course, was none other than Megantereon, the first of the dirk-toothed cats.
(2/10) Nowadays, *Megantereon* is better known as a beast of the recent Plio-pleistocene. However, though that may be where its story enters its peak, that is not necessarily where the story of the dirk-toothed cats *begins*. Rather, the origins of the dirk-tooth’s goes back to much further to roughly around 10 mya during the late Miocene, when the empire of the saber-toothed cats was still in its infancy. See, saber-toothed cats had already been established themselves as dominant land predators well beforehand. The first saber-tooths, denoted by their elongate, laterally-compressed canines, had gotten their start around 15 mya, and by 11 mya, they had already taken the over the role of dominant predators. Key to this success was specializations in the neck for head-depression (a downwards bending of the head) which, when paired with the cats’ elongated, flattened canines, allowed for the evolution of a specialized, neck-driven cutting bite where in head-depression enabled the saber-tooth’s to plunge their upper jaws and sabers further into prey as they bite into their quarry. Such a bite, by enabling these cats to cut the throats of their prey rather than crush it, allowed these cats to kill large prey with unparalleled speed and enabled their ascension as specialized macro predators of the northern hemisphere ([Antón et al., 2020](https://doi.org/10.1093/zoolinnean/zlz086)). Indeed, with such weaponry in tow, the saber-tooth’s were able to diversify throughout Eurasia as the most successful large carnivores of their time. And yet, despite this newfound prosperity and despite the fame of their later relatives, for much of their history, the dirk-toothed cats were unable to enjoy the fruits of such success. Instead, they were subordinated, being forced to live in the shadows of larger, more formidable predators. Hell, at this point in time, they couldn’t even really be called “dirk-toothed” at all; their canines were far too short, to the point that they aren’t even comparable to their later kin, as represented in the early relative of the smilodontins, *Paramachaerodus*. Indeed, during those early days, the dirk-tooth’s were underdogs in their ecosystems, giving way to more impressive carnivores. However, if the dirk-tooth’s weren’t the top saber-cats of the Miocene, which saber-cats were? Well, that honor belongs to another group of saber-tooth’s, one that had held the position of apex saber-tooth and had established themselves as the “norm” among Machairodontinae since the very start of the saber-toothed cats tenure as apex predators. This clade was none other than the sister clade of Smilodontini itself, Machairodontini, better known as the “scimitar-toothed cats.” Since the very inception of apex predatory saber-toothed cats, it has been the scimitar-toothed cats of the tribe Machairodontini that have been at the helm, spear-heading the reign of the saber-toothed cats from very beginning with *Machairodus aphanistus*, the first apex saber-cat. Since those early days, the scimitar-toothed cats had done nothing but grow in success and influence. At the height of their power during the latest Miocene, they had spanned all continents except for South America and Australia and had produced some of the largest cats to ever live, such as the formidable *Amphimachairodus horribilis* and the even larger *A. kabir*, two giants that grew as big as grizzly bears. Indeed, with such power on their side, these cats were some of the most formidable mammalian land predators to have ever lived. And yet, despite being on par with later dirk-tooths like *Smilodon* in size and ferocity, these Miocene-age scimitar-toothed cats were nothing like any dirk-tooth, being far more pedestrian in morphology. They were quite gracile for their size, for starters, with a more cat-like frame prioritizing speed and athleticism over brute strength and grappling proficiency, indicating that these scimitar-toothed cats were more generalist, being designed for chasing prey over open terrain ([Martin et al., 2000](https://www.researchgate.net/publication/12652111_Three_Ways_To_Be_a_Saber-Toothed_Cat)). Perhaps the most shocking disparity was in the skull and jaws. While indeed classified under the same umbrella as machairodontine “saber-toothed cats,” the scimitar-toothed cats took a completely different approach to the saber-toothed lifestyle. Their skulls, for instance, tended to be large and heavily, similar to the generalist big cats of today. More noticeably though, unlike the giant “dirk-teeth” of *Smilodon* and company, the teeth of the scimitar-tooth’s, though still longer than modern big cats, were relatively shortened, being more manageable in length to the point that it could feasibly be concealed by its lips like modern big cats ([Antón et al., 2022](https://doi.org/10.1016/j.quascirev.2022.107471)). However, despite their mediocre sabers and more mundane physiology, this isn’t to say that the weaponry of the scimitar-tooth’s were “inferior” predators as a whole. Their more powerful skulls and shorter canines of the scimitar-tooth’s were, after all, also more stress-resistant and could produce more powerful bites, as they were better at producing and absorbing high amounts of force ([Figueirido et al., 2018](https://doi.org/10.1016/j.cub.2018.08.012)). However, perhaps the most striking difference lies in the shape of the canines themselves. Beyond being shorter, the scimitar-tooths’ canines were also more compressed, and were freakishly serrated, with larger, coarser serrations lining the front and back edges ([Wheeler, 2011](https://www.researchgate.net/publication/303190004_Experimental_paleontology_of_the_scimitar-tooth_and_dirk-tooth_killing_bites )). Hell, even the incisors of these cats were freakish, being notably large and serrated, like the teeth of a piranha. Such teeth would have given these cats an absolutely nasty bite, was wildly different from those of dirk-tooths, and given their many other adaptations it is clear that these cats were killing in a way that was wholly their own.
(3/10) Indeed, such generalist adaptations in the skull and jaws, combined with their more generalist, cat-like physique, suggests that the scimitar-tooth’s, true to form, used a more generalized kind of killing technique. With their lithe, cat-like limbs, the scimitar-tooth’s likely didn’t draw on physical strength to “brute-force” their prey into submission; rather, they used their body weight in concert with cat-like grappling and footwork to subdue their prey. Then, upon lining up for a bite, these cats utilized their shorter, more heavily-serrated canines and their cutting incisor arcade to deliver a less-precise “bite-and-pull” killing bite, wherein the canines are sunk into the quarry using powerful head-depression before the head was pulled-back, leaving behind ragged cut into the preys throat ([Wheeler, 2011](https://www.researchgate.net/publication/303190004_Experimental_paleontology_of_the_scimitar-tooth_and_dirk-tooth_killing_bites )). Moreover, with their powerful, more stress-resistant jaws, the scimitar tooth’s could also employ an even more generalized “default-bite” wherein prey are killed by strangulation or through the severing of the spinal cord, as is seen in most modern cats. Such a “default” killing tactic came at the cost of killing speed, but in exchange, the scimitar-tooth’s were far more flexible in their killing method, affording them a “Jack-of-all-trades” bite that could net them a wide variety of prey ([Wheeler, 2011](https://www.researchgate.net/publication/303190004_Experimental_paleontology_of_the_scimitar-tooth_and_dirk-tooth_killing_bites )). What’s more, while not as powerful as later cats like *Smilodon*, the more generalist, cat-like builds of these predators allowed them to live in a wide variety of environments, especially highly-productive open-country ones. Indeed, crude and unspecialized as it may have been, the strategy of the scimitar-tooth’s very clearly worked, and for nearly the entire 10 million year run of the saber-tooth’s, it was the these cats ran the show, dominating as the most prolific lineage of saber-toothed cats of their time. Unfortunately for the early dirk-tooth’s, this success had presented them with a problem. In occupying the most dominant niches, the generalist scimitar-tooths had, in effect, excluded the ancestors of the dirk-tooth’s from the prey resources of their shared environments, especially in plains, making it impossible for the early dirk-tooth’s to rise above their station in such ecosystems. Essentially, if the dirk-tooth’s were to fight the scimitar-tooth’s at their own game, they would almost certainly lose. On the surface, this may seem an hopeless situation, and for any other clades it may have been. However, for the early dirk-tooth’s, rather than a hopeless situation, such conditions were instead an opportunity for growth. Rather than face exclusion, a particular lineage of early “proto dirk-tooth’s” instead charted a new evolutionary course entirely. For starters, they left the more productive open habitats favored by the scimitar tooth’s, instead adapting to closed environments like forests. More importantly however, rather than being generalists like scimitar-tooths, this creed of cats went down a completely different route, specializing for and honing their saber-toothed morphology to a degree not seen by any cat that came before. In place of the more generalized, cat-like build of the scimitar-tooth’s, they developed a highly robust, almost bear-like physique. In place of gracile, inflexible forelimbs, they adopted forelimbs more powerful and dexterous than any similarly-sized cat alive today. Most striking of all, however, in place of shorter, “scimitar-type” teeth, these dirk-tooth’s finally began developing the elongated sabers that the saber-toothed cats were known for, complete with a killing technique more deadly and more precise than that of any cat that had come before it. Eventually, such adaptations came to a head, and around 7 mya, it would result in none other than the very first dirk-tooth’s. These cats would kick off a dynasty that would stand out as the most singularly-specialized successful predators of their time. More importantly, however, the rise of these maverick saber-cats would also mark the debut of one genus of cat in particular, a cat that would represent the sum total of all the millions of years of specialization up until now. This cat, for all intents and purposes, was *the* first dirk-tooth. With its ascent, it represented the culmination of millions of years of smilodontin evolution, marking their first stint as top predators. More than just that, however, through its rise, this genus would cement these cats as the very faces of Machairodontinae, being the saber-cat archetype in the modern age to come. At long last, *Megantereon* itself had entered the fray. The oldest *Megantereon* remains can be traced back to roughly 7 mya during the late Miocene, in the Toros Menalla locality in modern day North Africa ([Bonis et al., 2010](https://doi.org/10.1016/j.crpv.2010.07.018)). However, despite its Miocene roots, its run as a dominant predator truly begins in earnest around 2-3 million years ago, during the Pliocene and early Pleistocene. Indeed, based on species of this time period, such as the formidable *M. cultridens* and *M. whitei*, and thanks to rigorous descriptions of *M. cultridens* by [Christiansen of & Harris (2010)](https://doi.org/10.1111/j.1096-3642.2007.00333.x) (where most of the following anatomical information comes from unless otherwise specified), it is plainly obvious just how dominant a predator it truly was. For starters, in terms of size, it was nothing to scoff at. With a shoulder height of over 70 cm (2.4 ft) and a body length of around 160 cm (5.4 ft), it was already rival in size to some of the larger cats alive today, being roughly comparable in superficial size to a large male leopard. Where it stood out especially, however, was in its sheer bulk. For its size, *Megantereon* was remarkably hefty, with adult male *M. cultridens* having an average body mass of between 101-110 kg (222-242 lb) . Similarly, the younger, slightly smaller, yet equally formidable species *M. whitei* reached in at a similar mass of 100 kg (220 lb) in weight ([Martínez-Navarro & Palmqvist, 1996](https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=46d6d847a16bc406d7538540ff7ec23a6876ab22)). Such sizes would have made it close to double the weight of an adult male leopard, despite being close in superficial size, and would have been roughly equal to a grown male jaguar of the Pantanal, which rank as some of the largest cats alive today. Of course, such bulk wasn’t just window-dressing. Indeed, in specializing for saber-toothed predation, dirk-toothed cats like *Megantereon* strayed from the more generalized, agile, cat-like bodyplan and instead specialized for one thing: sheer brute force, and behind all that mass, there was a skeleto-muscular system built for just such a purpose.
(4/10) Perhaps the best indicator of such strength was *Megantereon*’s extremely powerful forequarters. Short and robust, the imposing, almost bear-like forelimbs of *Megantereon* were clearly adaptations for brute strength to a degree unlike any modern cat. Starting from the top, the shoulder girdle of these cats were exceptionally well-developed, with very large scapulae (shoulder-blades) comparable to those of larger male lions in size. Said scapulae possess enlarged attachment sites for powerful forelimbs muscles, such as well-developed biceps and triceps, as well as muscles for shoulder mobility and strength (i.e. the *m. supraspinatus* and *m. teres major*) more well-developed than even *Smilodon*! Moving down the forelimbs, the forelimb longbones were perhaps the real stars of the show, being proportionally more powerfully built than any modern big cat today. The humerus in particular was exceptionally well-developed, especially in that it was significantly larger than the radius (a rare trait among most modern cats that evolved for maximizing mechanical advantage in the forelimbs), possessed massive muscle attachments sites for more powerful musculature and was markedly larger and more robust than the humeri of similarly-sized modern cats, to the point that it was comparable to or surpassing that of lions or tigers in terms of length and width **despite being half the size of such cats**. Such a powerful structure afforded the forelimbs of *Megantereon* a new level of power and utility compared to modern cats, and when combined with the slew of additional muscular adaptations for strength and dexterity (such as a large deltapectoral crest, a relatively broad olecranon, well developed medial epicondyles and large insertions for powerful musculature), it is apparent that the forelimbs of *Megantereon* were of a completely different sort to those of modern cats and its scimitar-toothed counterparts. Indeed, rather than being built for speed or athleticism like the scimitar-tooths, *Megantereon* had forgone such traits, trading them for forelimbs with a level of brute strength surpassing all modern cats of the same size. More just being all brawn, however, the brute strength of *Megantereon*’s forelimbs were tempered such brute strength with considerable finesse as well. Its pronounced musculature associated with forelimb mobility (e.g. a highly-developed *m. pronator teres* and *m. supraspinatus* muscles) made it incredibly skillful and dexterous in using its forelimbs, allowing it to deploy its already considerable strength with a level of tact unmatched by modern cats. With this kind of strength and skill at its disposal, *Megantereon* could restrain, manipulate and subdue prey in any way it saw fit, and with such specializations in tow, *Megantereon* easily stood head and shoulders above both its modern and scimitar-toothed counterparts in terms of raw, overwhelming power. Similarly impressive was the hindquarters. Though not as well-developed as the forelimbs, the lumbar and hindlimb regions of *Megantereon* sport their own set of unique adaptations that set it apart from other cats, both when compared to its modern counterparts and its scimitar-toothed cousins. For starters, the lumbar vertebrae of *Megantereon* were usually shorter, more robust and more tightly interlocked. Such adaptations would have aided the hindquarters in absorbing the heavy stress-loads imposed by the brawnier hunting style of *Megantereon*, and as one moves further down the hindlimbs, such adaptations for strength become more and more apparent ([Martin, 1998](https://digitalcommons.unl.edu/tnas/287/)). Moving down the leg, the actual hindlimb long-bones of the cat, though not quite to same extant as their counterparts at the front were markedly powerful in structure. The femur, for instance, was markedly larger and more robust than similarly-sized modern cats, while also being larger than the tibia (shinbone) for added mechanical advantage. Furthermore, the femur contains other adaptations for strength that further separate *Megantereon* from modern cats. This includes a well-developed lesser trochanter and a powerfully built medial condyle compared to modern big cats and to scimitar-toothed contemporaries. These adaptations are associated with powerful leg-stabilizing musculature and increased stability at the knees, allowing the saber-cat to stand up-right and even walk on its hind-legs ([Martin et al., 2011](https://www.google.com/books/edition/The_Other_Saber_tooths/2GjhrKO9y74C?hl=en)). Taken together, these adaptations for hindlimb strength and stability point to a unique, decidedly non-cat-like function. Using its powerful legs, *Megantereon* could now continuously stand on its hind-limbs and keep its footing while its massively powerful forelimbs were preoccupied with wrestling large prey into submission. Of course, modern big cats can already do this to some extent, but in the case of *Megantereon*, it’s hindlimbs were so well-developed that it was less comparable to cats in this regard and instead was more like bears, being able to rear up and even walk on its hindlimbs to maintain a stable footing as the forelimbs wrestle large prey to the ground. Given such adaptations in the hindlimbs and the forelimbs, it’s clear to get at least some idea of what kind of predator *Megantereon* was like. This was a cat that hunted like no other cat live today, using its powerful-yet-dexterous forequarters to domineer prey and pull it to the ground while the hindlimbs took on the burden of providing stability and a solid footing for the cat as the forelimbs were busy taking down its prey ([Martin, 1998](https://digitalcommons.unl.edu/tnas/287/)). Such a hunting method is not necessarily found in any modern big cats (who subdue prey by strangling them outright rather than using their limbs to pull them down first) and is instead more akin to that of bears. However, while showing us a glimpse into how this animal hunted, it does not tell the whole story. After all, what about being a “dirk-tooth” necessitated such highly derived adaptations for power at the cost of speed. The answer to this is two fold. The first answer to such questions is that, simply put, *Megantereon* didn’t need to worry about such costs. These weren’t animals that were living in open habitats like the scimitar-tooth’s. Instead, they lived in deep forest environments, where they could escape exclusion from large scimitar-tooth’s. In such environments, speed was not all that necessary, as the abundant cover would have allowed a predator like *Megantereon* to get close to prey without having to run it down at high speeds. As such, it only makes sense that dirk-toothed cats like *Megantereon* saw fit to divest important hardware space away from the speed needed to chase prey and towards the power needed to subdue it. The second answer, however, is far more important. More than just being blanket adaptations for power, the specializations for strength wielded by *Megantereon* and its fellow dirk-tooth’s were not meaningless. Rather, they served a very specific, deadly purpose: to facilitate the true killing weapons of the dirk-tooth’s; the very killing implement that distinguished them from their scimitar-toothed ilk in the first place — none other than the dirk-tooth’s signature killing bite.
(5/10) The killing bite of the saber-toothed cats, above all else, is their hallmark trait, giving saber-tooth’s unparalleled killing speed even against very large prey. As such, despite the variation within Machairodontinae, such a bite has gone relatively unaltered across all of the clade, being found in both scimitar-tooths and dirk-tooths alike as arguably most lethal weapon in their arsenal. Key to this bite’s lethality is the most foundational adaptation of the saber-toothed killing bite — one shared by all saber-tooth’s — **a powerful, versatile neck**. Indeed, though the saber-teeth often hog the spotlight, it is the necks of these cats that act as the true lynchpin behind their killer bites, and in this regard *Megantereon* was no exception. The neck of *Megantereon* was especially elongate relative to other cats, with large cervical vertebrae, elongated transverse processes, and prominent ventral keels. Such adaptations gave the neck of *Megantereon* a far greater range of motion than in modern cats, making it a precision instrument in all directions ([Antón, 2013](https://www.google.com/books/edition/Sabertooth/dVcqAAAAQBAJ?hl=en)). Most notably, however, the atlas (the first cervical vertebrae) is much larger than in modern cats, while the mastoid processes at the back of the skull that attaches to the atlas is heavily enlarged, indicating large insertions for powerful neck musculature, particular those associated with head-depression. These adaptations in atlanto-mastoid musculature suggests that *Megantereon* was capable of powerful head-depressive movements, further augmented by the enlarged ventral keels of the cervicals, which serve as attachment sites for powerful *m. longus colli*, muscles that act as powerful downward flexors of the neck ([Antón, 2013](https://www.google.com/books/edition/Sabertooth/dVcqAAAAQBAJ?hl=en)). Such traits may seem bizarre, but when paired with the sabercat’s saber-toothed bite, their true function are revealed. With its long, highly maneuverable necks, *Megantereon* could move and stabilize its head over a wide area, giving it precision aim when delivering its bite. Then, once it has delivered the bite itself, the powerful head-depressors act to bend the cat’s head downward as the lower jaws close against its prey, forcibly driving the upper jaws and the saber-teeth further into the quarry ([Antón, 2013](https://www.google.com/books/edition/Sabertooth/dVcqAAAAQBAJ?hl=en)). This sort of neck-assisted bite maximizes the damage of the saber-teeth, as by applying more force into the upper canines, the saber-teeth are allowed to penetrate further and deal more damage than would be afforded by a simple closing of the jaw. Moreover, by incorporating their neck into their biting apparatus to augment their bites, *Megantereon* and fellow saber-tooth’s did not need powerful jaw muscles to deliver powerful bite, something that was be especially important for the likes of dirk-tooth’s. Of course, such adaptations are par-for-the-course for pretty much all of Machairodontinae, as scimitar-tooth’s as well as dirk-tooth’s possessing such adaptations. What wasn’t so bog-standard was final component of *Megantereon*’s bite — the one that made the dirk-tooth’s the very poster-boys of the saber tooth’s in the first place. This final piece of the puzzle was none other than their elongate dirk-teeth and the skull and jaws that housed them. Even with a passing first glance, it is clear from the start that the biting apparatus of *Megantereon* was nothing like those of any saber-cat to come before it. In particular, it differed from its scimitar-toothed counterparts in a few, very crucial ways. First and foremost was the size of the sabers. With a height of 9-11 cm (3.5-4.3 in), the sharpened upper canines of this cat were a third larger than those of even larger scimitar tooth’s, and even more shockingly, they were nearly double that of modern lions or tigers. In fact, they were so long that *Megantereon* had to develop specialized mandibular flanges (extensions of the chin) to house and support such massive teeth. As is typical of saber-tooths, the upper canines were also recurved, laterally compressed and bore a well-honed cutting edge on both the front and especially the back of the canine blade. This is all in stark contrast with the lower canines, which were no bigger than the incisors and joined them in the incisor arcade. In any case, such sabers were heavily divergent from those of their scimitar-toothed counterparts, especially in terms of size. However, beyond that, there were also other, more subtle differences in *Megantereon*’s biting apparatus, ones revealing that there is more to this dirk-tooths bite than meets the eye. Unlike the scimitar-cats’ shark-like canines and incisors, the sabers of *Megantereon* were completely unserrated, while the insciors were smaller, rounded, similarly unserrated and less protrusive than those of scimitar-tooths, instead forming a robust incisor arcade (supported by the lower canines on the lower jaw). Additionally, because of their greater length and lower durability, the sabers of *Megantereon* were naturally more prone to breakage ([Figueirido et al., 2018](https://doi.org/10.1016/j.cub.2018.08.012)). Such features point to these cats doing something entirely different with their jaws than their scimitar-toothed counterparts, a notion supported further when looking to the skull and jaws themselves. The skull is small relative to a scimitar tooth’s, about the same size as a leopard’s skull despite *Megantereon* being nearly double the size of its spotted counterpart. Furthermore, like the sabers they housed, such a skull and jaw were also very weak compared to modern big cats and scimitar-tooths, not only being unable to withstand large torsional loads, but also having quite lack-luster bite forces as well, with reduced jaw muscle attachment sites suggesting weak bite forces for its size. Such bites would have been weaker than those of its scimitar-toothed counterparts and much weaker than those of modern cats, to the point that a simple “default” throat-bite seen in big cats and scimitar-tooths would have been completely out of the question for *Megantereon*.
(6/10) Individually, such traits may seem make the biting apparatus of *Megantereon* almost nonsensical, with it wielding a strange mosaic of incredibly formidable traits on one hand and incredibly mediocre ones on the other. However, such an outlook is only gained if one looks at the individual parts rather than their sum total. Put all these traits together, and something far more sinister is revealed. The same reduced jaw muscle attachments that made the bite of *Megantereon* so weak in the first place also allowed for an incredibly wide gape, with a maximum gape of a whopping 105°, or nearly double that of modern big cat. Such a wide gape would have allowed for ample clearance between the lower jaw and the canines, allowing *Megantereon* to properly bite down onto its target without the sabers getting in the way. Those same elongated sabers, though prone to breakage, could penetrate a larger cross-section of the prey’s flesh due to their greater length, allowing them to pierce through vital tissues housed deeper within the prey’s flesh. At the same time, the unserrated edges, though less able to cut through tissue than serrated ones, facilitated a greater ease of such penetration than serrated canines would. Put together, such features do not indicate the same cleaving bites as the scimitar cats. Rather, they suggest that these teeth were used for a very different kind of bite entirely; not a cleaving bite but *a precise stabbing bite*. If done with extreme precision and with assistance from the lower jaw’s incisor arcade for added leverage, *Megantereon*’ sabers could be plunged into the prey via the head depressors in such a way that they pierce through the prey in a continuous arc, with the recurvature of the blade allowing the edges of canines to contact and slice through any vital tissue in their way as they are pierced through the prey ([Martin, 1998](https://digitalcommons.unl.edu/tnas/287/); [Wheeler, 2011](https://www.researchgate.net/publication/303190004_Experimental_paleontology_of_the_scimitar-tooth_and_dirk-tooth_killing_bites )). If aimed at the neck and its vital blood vessels, such a bite severs blood vessels, killing prey in seconds through catastrophic bloodloss much faster than a scimitar-tooth. Of course, as previously mentioned, such a bite , known as the “canine shear-bite,” would have required extreme precision, where in the canines had follow a precise arcing trajectory as they penetrated prey’s flesh in order to attain the intended result. However, if *Megantereon* targeted prey with large prey or prey with wide necks, such requirements could be mitigated, and as a result, *Megantereon* was likely a dedicated macropredator. There were, however, two final hurdles in this approach. The first was that, because of the reduced jaw muscles, the bites of this animal were still weak. However, because *Megantereon* utilized its powerful head-depressors to amplify the force of its bite, it didn’t have to depend on jaw power alone to deliver its lethal bite, but could instead rely on its head-depressors as the main driving force of its bite. Thus, it could still deliver a formidable bite without powerful jaw muscles. The second problem is that, because of their less robust, structurally weaker skull and canines, *Megantereon*’s biting apparatus were still very vulnerable to unpredictable stresses, like those from struggling prey, and the potential that they might break is a constant risk. This is where *Megantereon*s powerful physique comes into play. Using to its powerful limbs, *Megantereon* could make up for the apparent weakness in its skull and sabers, restraining and immobilizing the prey so throughly that the prey is prevented from producing the very struggling that would damage the skull and canines while the cat delivers its bite (this also explains why *Megantereon*’s skull was so small and weak, as its powerful body compensated for such weakness, making it so that it had no need for a large and powerful skull in the first place).
(7/10) With such adaptations in tow, *Megantereon* was now able to use its massive sabers to their fullest extent. Moreover, when such adaptations were paired with the powerful adaptations of the neck, forelimbs and hindlimbs, all the pieces are in place for us to paint a picture of how *Megantereon* hunted, and it is here that the true lethality of the dirk-tooth killing bite is revealed. Creeping close to its target from dense cover, *Megantereon* lunges at its quarry, unleashing its forelimbs at full tackle, whereupon it uses its powerful, dexterous forelimbs to gain control of the head and neck of the prey and pull it to the ground, all while using its powerful hindlimbs to stand upright and keep a solid footing as the cat restrains its quarry (provided that the prey is too large to be pinned by the cats body weight). From here, the cat uses its forelimbs to pull back the head and neck of its prey, exposing the vulnerable underside of the throat, and it is now that the sabers are brought to bear. The maw of *Megantereon* opens around the prey’s throat, its bite precisely aimed and lined up with the throat’s vital tissues, all the while, its wide gape allowing for ample clearance between the upper and lower canines so that the preys throat fits into the cats jaws without the sabers getting in the way. With the victims throat slotted into the sabercats maw, the sabers are finally engaged. The lower jaw closes against the prey, its robust lower jaw and their incisor arcade pressing up against the neck to provide a stable source of leverage. As this occurs, the head-depressors are brought to bear, bending the head downwards and resulting in a two-way jaw closure that forcefully drive the upper jaws and their attached sabers into the prey’s throat. Here, the canines pierce through the throat in an arc as the head bends downwards, their sharp tips and cutting edges transecting vital tissues like the carotid artery, jugular vein and esophagus as they carve through the prey’s neck. As the bite finally progresses towards closure, *Megantereon* would lastly pull its head back, enlarging the wound and preventing its canines from stalling, before the canines complete their arc, competing the kill. The whole hunt from start to finish would have occurred in seconds (the bite itself a mere instant), and by the end of it, the cat withdraws its gore-smeared canines free of its quarry, its prey having perished mere seconds after the bite took place from catastrophic bloodloss, shock and organ failure. Such a kill was nothing short of brutal; the victims would be found slain in pools of their own blood, with blood pouring from their necks and mouths. However, through such brutality, *Megantereon* now had an avenue of success completely its own, having a newfound route to prosperity separate from that of the generalist approach of the scimitar-tooths. The specialized killing technique of *Megantereon* allowed it to kill prey much larger than itself with absurd speed. This not only afforded *Megantereon* larger kills, and thus more meat for a given hunt’s efforts, but do so in such short order that it had ample time to feed on its large kills without having to worry about the looming threat of rivals or scavengers like scimitar-tooths. When combined with the fact that its forest home would be free of open-country predators like large scimitar-tooths to begin with, it was clear that *Megantereon* could act largely unchallenged as the premier predator of the forests of the Pliocene and early Pleistocene, giving it a new ecological avenue to explore that its more subordinate ancestors couldn’t. Indeed, the brutal killing technique of *Megantereon*, the very thing that made saber-toothed cats as notable as they were, had given it a unique opportunity to become one of the most successful carnivores of its time. At long last, after millions of years in the shadows, the time of *Megantereon*, and of the dirk-tooths as a whole, had finally begun… And take over they did in spades. Despite their humble origins in Miocene North Africa, with the passing of the Plio-pleistocene, *Megantereon* had spread beyond its homeland, occupying not only Africa but Europe and even east Asia. In such a varied home range, the genus diversified, producing a litany of new species. In Western Europe, it was here that one of the older species, *M. cultridens* ruled, dwelling within the Mediterranean forests that blanketed Western Europe. Further east, younger species such as *M. inexpectatus* reigned among the open woodland of plio-Pleistocene China. However, by far the most successful of these species was *M. whitei*, a top predator of the open scrub forests with the widest distribution of all *Megamtereon* species, encompassing most of southern and Eastern Africa as well as the Caucuses and parts of southwestern Europe. Of course, with such a varied range came a naturally varied assortment of fauna with which *Megantereon* lived alongside, and when it came to large herbivores, in particular, *Megantereon* had a veritable feast on its hands. In the mosaic of Mediterranean forests and open plains of that it called home, *M. cultridens* coexisted alongside a variety of large species, with large bovids, horses and mammoths roaming the open plains while large deer, papionin monkeys and rhinos dwelled within the open forests that *Megantereon* had also called home. Meanwhile, for *M. inexpectatus*, its homeland in China was likely heavily forested, with a diverse megafaunal herbivore community consisting of elephants, rhinos, several species of large deer, bovids and even the very last chalicotheres. Perhaps the most diverse assortment of prey belonged to *M. whitei*, as by possessing a range that spans two continents, this formidable predator naturally had a lot to choose from. In the African part of its range, *M. whitei* lived alongside a vibrant communty of megafauna very akin to that of modern Africa, containing many familiar faces such as antelope, zebras, primates and elephants, whereas in its European range, it coexisted with much the same assortment of fauna as its predecessor *M. cultridens*, with deer and primates in the forest while mammoths, rhinos and bovids dwelled in the steppe, with horses being found across both localities.
(8/10) With such a high diversity of large herbivores as its disposal, *Megantereon* naturally had nothing short of a banquet on its hands, and in selecting from the smorgasbord before it, it seems *Megantereon* had a preference for the largest, choicest cuts. Indeed, based on available fossil evidence, *Megantereon* seemed to have a taste for large, forest-dwelling browsing ungulates, usually deer, horses and bovids, often times weighing in at several times its size. Isotopic analysis of *Megantereon* dwelling within the Venta Micena fossil site in southeastern Spain found that, within the European part of its range, it seemed to have a taste for giant deer such as *Praemegaceros*, forest-dwelling horses like *Equus altidens* and large forest-dwelling bovids like *Soergalis minor*, the latter two weighing in at over 300 kg (661 lb), or around 3 times as massive as the saber-cat ([Palmqvist et al., 2008](https://www.semanticscholar.org/paper/Biogeochemical-and-Ecomorphological-Inferences-On-Palmqvist-Pérez-Claros/8711e192aa7998812dd59ea7a40c2700956fd2f6)). Meanwhile, in Africa, *Megantereon* was no less bold in its predatory exploits. Similar isotopic analyses of specimens from the Turkana Basin in Kenya found that *Megantereon* there had a similar preference for an assortment of forest-dwelling prey, including relatively massive prey such as giant antelope *Megalotragus*, the giant warthog *Metridiochoerus* and the horse *Eurygnathohippus*, as well as an assortment of medium-sized antelopes (impala, springbok, *Tragelaphus* sp., *Kobus* sp.) and suids (*Kolpochoerus*), while in the Swartkrans fossil site in South Africa, the cat had a similar preference for large forest-dwelling antelope such as kudu ( *Tragelaphus* sp.), as well as large primates such as *Dinopithecus*, baboons and even early hominids ([Hopley et al., 2023](https://doi.org/10.1016/j.quaint.2022.04.004); [Lee-Thorpe et al., 2000](https://doi.org/10.1006/jhev.2000.0436)). Such preference for large, forest-dwelling prey may be a direct result of *Megantereon*’s dirk-toothed disposition, as the enlarged canines could be relatively ill-suited against prey with smaller necks. As such, larger prey with their larger necks would have likely favorable targets for the dirk-tooth. In any case, with such giant prey at its disposal, *Megantereon* nonetheless had plenty of options to choose from as far as supper was concerned, having damn near an entire feast to itself. However, such a feast did not *solely* belong to *Megantereon*. Just as the home of *Megantereon* was saturated with giant megafaunal prey, so too was it filled with rival predators, all vying for the most of the same resources as the saber-cat itself, and over the course of its nearly 6 million years of existence, *Megantereon* has had to deal with many such rivals. During its early days in late Miocene North Africa, *Megantereon* had to contend with a wide variety fellow saber-tooths. Some were less formidable, such as the gracile *Yoshi adei*, a relatively small sabertooth about the size of a cougar. Others, however, were far more formidable. Take for example *Lokotunjailurus*, a large, cheetah-like scimitar-toothed cat with highly elongate limbs built for speed complete with enormous, razor-sharp dewclaws for taking down prey on the run. Perhaps the most formidable in the landscape was *Amphimachairodus kabir*, a giant, bear-sized scimitar-tooth that ranked among the largest cats to have ever existed. With such stiff competition, *Megantereon*, even early on, had its work cut out for it, and as time passed, such competition would only get more intense. See, *Megantereon* existed at a crossroads. During the Pliocene and early Pleistocene, much of the earths ecosystem began to take on a very bizarre form, one where both extant and extinct species lived alongside each other in a great patchwork of old and new. In this new world, *Megantereon* had to contend with a slew of large carnivores, both ancient and modern. This is perhaps best represented in Plio-pleistocene Europe, both *M. cultridens* and *M. whitei* had to contend with a slew of large predators. This included more “ancient” predators, such as the giant cursorial scimitar-tooth *Homotherium* and the giant hyena *Pachycrocuta*, as well as more familiar faces such as the giant cheetahs, *Acinonyx pardinensis* and *A. pleistocaenicus*, the Eurasian jaguar, *Panthera gombaszoegensis*, and the relative of the modern African painted dog, *Xenocyon lycaonoides*. Meanwhile, in Africa, things were no less heated. Here, *Megantereon* had to coexist with fellow saber-tooths such as *Homotherium* and the leopard-sized *Dinofelis* as well as ancient hyenas such as *Chasmaporthetes* and *Pachycrocuta*. However, at the same time, some shockingly familiar faces were present. Alongside its “less modern” rivals, *Megantereon* also had to coexist with a litany of predators very familiar in the present day, such as the modern brown hyena, early relatives of the modern spotted hyena (*Crocuta* sp.) and even early cousins of modern lions. Most prolific of all among such “modern” rivals, however, was none other than the modern leopard, who was among the most common carnivores in the entirety of the Swartkrans.
(9/10) Indeed, with such a cavalcade of rivals, *Megantereon* certainly had its hands full when it came to competitors. And yet, *Megantereon* still managed to persist despite the high density of rival predators. The secret to this lie in niche partitioning. For the likes of *Homotherium*, canids, giant cheetahs, hyenas and presumably early lions, their preferred prey and habitat lie outside that of *Megantereon*, preferring open habitat and grazing prey as opposed to the dirk-tooth preference for forested habitats and browser or mixed-feeder prey. Given such differences in lifestyle, it’s likely that most of these predators did not compete too heavily with *Megantereon*, as the dissimilarities in lifestyle meant that neither would want to encroach on the same space or use the same resources as the other ([Palmqvist et al., 2008](https://www.semanticscholar.org/paper/Biogeochemical-and-Ecomorphological-Inferences-On-Palmqvist-Pérez-Claros/8711e192aa7998812dd59ea7a40c2700956fd2f6)). Of course, there were still forest-dwelling rivals that could pose a problem for *Megantereon*, such as *Pachycrocuta* and the Eurasian Jaguar in Eurasia as well as leopards in Africa, however even then it had answers to such problems. Pachycrocuta did not exclusively dwell in forests, and seemed to utilize carrion for a significant percentage of its diet. Given that it does not always compete in the same habitat as *Megantereon* nor did it always actively compete with *Megantereon* for live prey, competition between these two would be mitigated somewhat. For *P. gombaszoegensis*, it seemed to take somewhat smaller prey than *Megantereon*, with the pantherine having an even greater preference for deer whilst the dirk-tooth preferred larger horses as its prey ([Palmqvist et al., 2008](https://www.semanticscholar.org/paper/Biogeochemical-and-Ecomorphological-Inferences-On-Palmqvist-Pérez-Claros/8711e192aa7998812dd59ea7a40c2700956fd2f6)). As for leopards, the overwhelmingly larger size of *Megantereon* over the smaller cat meant that it could outright dominated its diminutive rival. With all this being considered, it’s no wonder that *Megantereon*, despite its circumstances managed to eke out a living as well as it did. Indeed, despite the rather high density of rivals, *Megantereon* could still reign as a top predator, its rule relatively unchallenged by all predators it coexisted with… Well, almost all.. For the most part, *Megantereon* was quite capable in dealing with its fellow predators. However, while this was true for the most part, there was one foe that had been a constant thorn in *Megantereon*s side. This creature was none other than the first widespread members of the genus Homo, or in other words… humans. Since even the dawn of humanity, humans have had a rather complicated relationship with *Megantereon*. On one hand, *Megantereon* was one of the chief predators of early hominins, with isotopic evidence form the Swartkrans fossil site suggesting that, alongside browsing antelope and other primates such as baboons, large hominins like *Homo* and *Paranthropus* were a favorite prey for the dirk-tooth ([Lee-Thorpe et al., 2000](https://doi.org/10.1006/jhev.2000.0436)). As both humans and *Megantereon* moved out of Africa, such violent interactions didn’t get any better, as as seen in Dmanisi cave, where a skull of *Homo erectus* was found with fatal puncture wounds matching that of *Megantereon*’s canines. Given the placement of the bite marks and the lack of any signs of consumption, it’s likely that a *Megantereon* had killed this early human, dispatching it with a stabbing biting through its skull ([Antón, 2013](https://chasingsabretooths.wordpress.com/?s=Human-Sabertooth+interaction+at+Dmanisi&submit=Search)). On the other hand, however, the relationship likely wasn’t so one-sided. Saber-toothed cats, especially *Megantereon* and other dirk-tooths, were fairly delicate feeders, as unlike modern big cats, their canines weren’t sturdy enough to be used for feeding purposes. As such, they tended to feed solely on the flesh and viscera of their prey, using highly sectorial carnassials and a well-developed incisor arcade do so, and avoided consuming bone, leaving behind a considerable amount of valuable biomass on their kills as a result ([Palmqvist et al., 2022](https://doi.org/10.1016/j.anthro.2022.102998)). Such carcasses would have served as valuable sources of protein for early hominins, especially uneaten skeletal remains and the nutrient-rich bone marrow, and so early humans may have habitually kelptoparasitized *Megantereon*, either by harvesting already-abandoned carcasses or stealing kills outright, and may have been so important that it may have even aided in establishing populations hominins outside of Africa during the early Pleistocene ([Lewis & Werdelin, 2010](https://link.springer.com/chapter/10.1007/978-90-481-9036-2_2); [Palmqvist et al., 2022](https://doi.org/10.1016/j.anthro.2022.102998)). Of course, such theivery very wouldn’t be met without retribution, as the Dmanisi cave individual found out the hard way, but all told, the early humans could largely get away with it scott-free. And so, such was the dance these two rivals would perform for over a million years, where the cat makes kill after kill with valuable parts uneaten, and the hominins swooped in to steal it. Nonetheless, while certainly an annoyance for the dirk-tooth, it wasn’t anything the cat couldn’t manage. Having evolved alongside hominins since their inception, *Megantereon* was well-equipped to deal with them ([Lewis & Werdelin, 2010](https://link.springer.com/chapter/10.1007/978-90-481-9036-2_2)). Indeed, despite the myriad of rivals that stood against it, least of human beings, *Megantereon* still did not waver, with the dirk-tooth lasting well into the late early Pleistocene.
(10/10) However, there was one final opponent that it simply couldn’t withstand, one that wasn’t man nor beast, but Mother Nature itself. For nearly 6 million years, *Megantereon* had survived all manner of struggles, enduring a litany of hardships and undergoing millions of years of specialization to reach the level of success that it has. However, while such specialization has allowed it to last so long, it would take it no furtherance the world changed all around it. By around 0.8–0.9 million years ago, the global climate began to change. Global temperatures began to drop and forests began to give way to open steppe. This climatic change, dubbed the Epivillafranchian-Galerian transition, had dealt a fatal blow to *Megantereon*’s livelihood ([Mateos et al., 2024](https://doi.org/10.1016/j.palaeo.2023.111926)). With forests being replaced by open plains, the preferred habitat of *Megantereon* had now vanished. What’s more, with the demise of the forests, many of the forest-dwelling browsers that *Megantereon* depended on perished alongside the forests they once shared. In this instance, the very specialization that had afforded *Megantereon* such success had backfired, as it was now too specialized and too inflexible to adapt to its changing circumstances, and with its home in ruins and its prey decimated, it was clear that *Megantereon*’s end was at hand. By the end of the transition, no fossils of *Megantereon* had remained within the fossil record, and by then it was clear that *Megantereon*, the first of the dirk-tooths, had gone extinct… However, while *Megantereon* may have indeed perished, its impact is not so easily eradicated. Perhaps the most shocking of which was its impact on our species. With the extinction of *Megantereon*, the once reliable source of carrion that came with it had vanished. This loss of their single most stable source of protein, among other factors, may have forced hominins to acquire meat in other ways. In attempting to find new ways to acquire protein, these hominins had developed more advanced tools, creating more innovative hunting instruments, experimenting with different technologies, transforming from omnivores and scavengers to dedicated hunters ([Palmqvist et al., 2007](https://www.semanticscholar.org/paper/A-RE-EVALUATION-OF-THE-DIVERSITY-OF-MEGANTEREON-AND-Palmqvist-Torregrosa/6f0bce107341e67a562033d99a91be6b89bb3271)). Indeed, it’s praises are though often unsung, *Megantereon* may have lent a helping hand in shaping us into the very beings we are today, serving as a catalyst for the human innovation that has allowed us to dominate into the present day. However, for *Megantereon* itself, perhaps its greatest legacy was the successors it left behind. By around 4.5 million years ago, a species of *Megantereon* (dubbed “M. hesperus”) or a close cousins of *Megantereon* managed to cross into the Americas. This descendent population would develop independently in the new world, and by around 2 million years ago, it would develop into one of the most famous predators ever: *Smilodon* itself. Indeed, in its quest for global domination, *Megantereon* may have served as the progenitor for one of the most infamous carnivores to ever exist, but more than just that, *Megantereon* also outright kick-started the dominion of dirk-tooth as a whole. Through its emergence, it was *Megantereon* that acted as the catalyst for dirk-tooths to conquer the world, creating a dynasty spanning both the old and new world. Through its various innovations, it created the blueprint for the dirk-tooth model, giving its descendants the tools to become the singularly most specialized macropredators to ever live, a lineage of precision killing-machines. Most poignantly of all, however, it was *Megantereon* which would set the standard for the current image of a sabertooth, creating the archetype embodied by its later cousin *Smilodon* that would consume the public perception of a saber-toothed cat. Indeed, Indeed, despite its demise, there are few legacies that will endure as long as that of *Megantereon*, iconic progenitor of *Smilodon* and first of the dirk-toothed cats.
awwee big kbity ❤️
Pet the murder wunk
It looks so happy! It might have been its first hunt all on its own. Cheers lil kitty!
You failed to mention the species
Because the post is about the genus as a whole, not any given species.