Homotherium, slayer of giants?
The spectacular fangs of sabertooth cats have been often seen as possible adaptations to pierce the hide of giant, thick-skinned prey such as proboscideans. But living elephants are such formidable creatures that it is difficult to accept that they would be the main targets of any mammalian predator. And yet there are pieces of evidence which clearly show that, at least in some instances, sabertooths did hunt proboscideans.
At Friesenhahn cave in Texas ( a fossil deposit of late Pleistocene age) the bones of several sabertooths of the genus Homotherium, including individuals of different ages, were found in association with those of many mammoths and mastodons. The place was in all likelihood used as a den by the cats, and the proboscidean bones show clear tooth marks, proof that the sabertooths were eating from them at the site. The proboscidean bones corresponded to animals between 2 and 4 years of age, a time when they are still of “manageable” size for the predators, but less closely vigilated by the mothers who need to concentrate in protecting their younger, more vulnerable calves.
But even at such young age, elephants make rather inconvenient prey. Even with the long and flattened canines of Homotherium, the diameter of the elephant neck is just too big and the skin too thick for an efficient killing bite to take place, so the dispatching of prey is by necessity long as it gets slowly weakened through blood loss from relatively superficial wounds. On the other hand, the sheer size and strenght of even a calf of this age makes it very difficult for a single cat to keep it pinned down to the ground. This disadvantage is made more serious by the fact that Homotherium, unlike other sabertooths, had long forelimbs with narrow wrists and small, not fully retractable claws (except for the enormous dewclaw).
The scene below shows a group of Homotherium and a young mammoth in the early Pleistocene of Southern Spain.
So, if we look at the overall anatomy of Homotherium we see that it was not an ideally built “elephant killing machine”. In terms of the ability to single-handedly wrestle down a large prey, even a lion is better equipped, but then the sharp canines of Homotherium were a real advantage to inflict nasty, debilitating wounds.
For me, there are 2 conclusions to be gained from this overview of the evidence:
First, that in order to bring down young proboscideans as the Friensenhahn cave sabertooths obviously did, hunting in a group would be a distinct advantage, and in fact it was probably a necessary condition.
Second, that since the overall body build of Homotherium was not that of a “giant slayer”, the odds are that the systematic elephant predation we see at Friesenhahn was either a local phenomenon, or a seasonal one, or both. Elsewhere and at different times of the year, there was probably a variety of prey for Homotherium to take, but my guess would be that it most often concentrated on ungulates of horse to bison size, and whenever it had to hunt individually, it would certainly go for lighter animals like horses or antelope.
So, giant slayer? potentially yes, but only under the right circumstances.
To learn more, look for the book “Sabertooth” in late october!