Was Smilodon a prehistoric can-opener?

La Brea

A Smilodon fends off vultures at what would later be called the Rancho La Brea tar pits, situated in Los Angeles, California. Painting by Charles R. Knight.

The feeding habits of saber-toothed cats have long perplexed scientists. How in the world did these cats kill prey with their almost comically-oversized teeth? Did Smilodon and its kin use their teeth like daggers to stab prey to death, or did they simply rip out a huge chunk of flesh from the side of a victim, leaving their prey to hemorrhage to death?

While the stabbing hypothesis has generally been abandoned it is still a mystery how sabercats used their immense canines, especially since there were three different types of saber-toothed cats which differed in their killing techniques. Perhaps the characteristics of the prey animals themselves could provide some clues as to how the felids might have fed. There may be more than one way to attack a mammoth or giant sloth, but some ways would certainly have been better than others.

Frustratingly, however, figuring out what prey sabercats favored has been a difficult task. For a long time this subject was simply a matter of conjecture. In 1846, for example, Richard Owen delivered a lecture to the annual meeting of the British Association for the Advancement of Science in which he took the heavily-armored hides of the glyptodonts to indicate that they were a favored prey of sabercats in South America. A summary of his report stated;

Prof. Owen thought that the present knowledge of the co-existence with those large herbivorous Armadilloes [i.e. glyptodonts] of a gigantic carnivorous species like Machairodus [a genus of large sabercat, but probably actually Smilodon in this case], gave some insight into their need of a complete and strong defence of all the exposed parts of the body and the tail, since they had not the powerful claws with which the Megatherioid quadrupeds [i.e. giant ground sloths] might have waged war with the Machairodus.

Whether such defensive armaments were created through the operation of natural law or were bequeathed by a designer who liked to see the mammals go at each other in gladiatorial combat is left unstated.

La Brea

The glyptodonts Doedicurus (with the spiked tail) and Glyptodon. From W.B. Scott’s A History of Land Mammals in the Western Hemisphere.

The American paleontologist E.D. Cope echoed Owen’s conception of the dining choices of sabercats in his On the Extinct Cats of America. Cope speculated;

The known species [of Smilodon] belong to the Pliocene period, and were the cotemporaries of the gigantic sloths and Glyptodons, which at that time ranged over the entire American continent. Their powerful limbs terminated by immense claws, bespeak for them exceptional force in striking and tearing their prey, and the long compressed canine teeth are well adapted for penetrating the tough hides and muscles of the large Edentata [i.e. giant sloths and glyptodonts], which were doubtless their food.

It all seemed very simple. Smilodon was a massive, heavily-muscled cat with extremely elongated incisors that lived in the same habitat as sloths with huge claws and glyptodonts protected by shells made of osteoderms (some even had a little cap made of osteoderms to protect their heads). Clearly the depredations of Smilodon and its kin had driven this evolutionary arms race, and the American paleontologist Frederic A. Lucas thought that the cat used its teeth as something like a can-opener. In his 1902 book Animals Before Man in North America Lucas wrote;

If [Smilodon] preyed upon the ground sloths, as Professor Cope suggested, the use of their enormous canine teeth seems evident. The sloths are covered with coarse hair implanted in a thick hide, and some of the mylodons were even protected by numerous small bones embedded in the skin. While such a creature might not be invulnerable to the attacks of an ordinary beast of prey, it is evident that our largest cat, the jaguar, might beat and bite his huge carcass in vain. But the powerful teeth of smilodon, like two daggers, would reach through hair and hide to the deep-seated arteries of the neck, and before such a foe the big, sluggish mylodon would go down.

The elongated fangs of the sabercats were seen by Lucas and others as adaptations that allowed them to take down large, thick-skinned prey like giant ground sloths and elephants. It seemed clear that the largest of the sabercats were probably adapted to capture and kill prey much larger than that preferred by modern tigers and lions. (Though both these cats can take down very large prey, especially prides of lions.) As with modern large carnivores, however, it appears that at least some sabercats preferred the young of large prey species. This is evidenced by an accumulation of the bones of young mammoths collected by the far-ranging sabercat Homotherium in a Pleistocene-age cave in Texas. Taking down adult mammoths or even large ground sloths would be a very dangerous undertaking, indeed, so the young of megaherbivores might have been just big enough for the ancient felids without imposing as much as a risk.

Given their hypercarnivorous habits, though, large sabercats like Smilodon and Homotherium could not rely on juvenile prey all year. They could not switch their diets to whatever food source was most abundant throughout the year like modern bears do. They had to keep hunting, but the details of their predatory habits likely varied from place to place and species to species, so it is difficult to come up with a comprehensive picture. (The most detailed analysis to date can be found in The Big Cats and Their Fossil Relatives.)

Indeed, while I have focused on Smilodon here due to its familiarity many other kinds of saber-toothed cats lived during prehistory. Assuming that they all had the same type of saber-teeth and used them in the same ways would be like saying that all prehistoric proboscideans (elephants, generally speaking) had the same tusk morphology and used their tusks in the same way. We know that this just isn’t so, but it can be difficult to get across when there is just one flagship genus that everyone knows. Add to this the fact that some sabercat genera were far-ranging and long-lived and you have to account for potential variation of habits within those genera; how did Smilodon in North America differ from Smilodon in South America, for instance?

Despite its familiarity, though, we still have a lot left to learn about Smilodon. What it hunted, how it hunted, and why there are no more sabercats alive today are questions that remain difficult to fully grasp. Fortunately, though, scientific discussions about Smilodon have moved beyond just idle theorizing, and perhaps someday we’ll have a more complete understanding of how Smilodon and its kin used their fearsome dental apparatus.

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