A Clash of Titans: Lion Vs Scimitar-tooth Cat
A former “pet theory” about the sabertooths was that they were specialized for hunting giant, slow and thick-skinned prey, and that when those herbivore behemoths went extinct, the sabertooths found themselves unable to capture the faster, smaller prey such as horses and antelopes. Then sabertooths went extinct, while the modern cats triumphed, because the latter were fast and smart and so they could chase and even use group tactics to catch the fast prey animals.
So the thory went, but it was largely based on the observation of the fossils of Smilodon, which is the heaviest, most robust of the sabertooth cats. Even for Smilodon the theory is certainly wrong, but the fact is that also in the Pleistocene there lived another kind of sabertooth: Homotherium, the so-called scimitar-tooth cat. In the Old World, Homotherium coexisted with the lion for many thousands of years, and when one compares the anatomical structure of these two top predators there are quite a few surprises to be found:
Homotherium was not a slower or heavier animal than a lion. In fact it was on average a lighter animal, especially when compared with the Pleistocene lions of Europe that were larger than their modern counterparts. You can see that difference at a glance looking at the drawing below, where both animals are shown to the same scale: the Pleistocene lion is shown at left (life outline on top, skeleton at bottom) and Homotherium at right. Homotherium had comparatively long forelimbs, and its wrist was narrower, better adapted to running and less adequate for handling prey.
The claws of Homotherium were smaller and less retractable than those of the lion, except for the large dew-claw, as happens with the living cheetah, again adaptations for sustained running rather than grappling heavy prey.
The teeth of Homotherium were precision tools perfect for cutting the throats of large prey animals, but given that each individual cat was more of a runner and less of a wrestler than an individual lion, there is one clear implication: in order to hunt the animals that its teeth were adapted to kill, a cat with the limb anatomy of Homotherium almost inevitably had to hunt in groups.
The size of the upper canines limits the diameter of the necks of prey animals that Homotherium could bite, so it is clear that it would not hunt adults of giant species such as proboscideans, rather it would target animals within the high part of the size range of the prey taken by lions, that is: large bovines, horses and the young of the giant species.
So we see a lot of overlapping and potential competition with lions, more so than the old cliché of the sabertooths as slow brutes would have us think. So now new questions arise: how did those animals avoid the worst of competition for so many thousands of years? And how did the lion manage to survive the crises of the Pleistocene that killed off the sabertooths and so many other species of large mammals?
Those are good questions indeed… and evidence points to some rather surprising answers. That evidence is discussed at some length in the upcoming book “Sabertooth”. Stay tuned!