Saber-Tooth Cats, Dire Wolves Found in La Brea Tar Pits Show Wounds From Ice Age Battles

The bones of saber-tooth cats and extinct dire wolves, extracted from sticky pits of natural asphalt in downtown Los Angeles, still bear the marks of injuries sustained in battle more than 11,500 years ago, researchers say.

And the scarred remains reveal the different hunting strategies used by these Ice Age predators, producing distinctive patterns of fractures, strains, and even osteoarthritis that are unique to each species.

Saber-tooth cats — known as Smilodon fatalis — lived in North America from about 500,000 to 11,000 years ago and have no direct living descendants.

(Learn more about where they came from: “America’s Saber-Toothed Cats Weren’t ‘Native,’ Study Finds“)

And dire wolves “are not made-up beasts for ‘Game of Thrones,’” quipped Caitlin Brown, a UCLA doctoral student in ecology and evolutionary biology, who led the new study of the remains.

Instead, dire wolves, aka Canis dirus, were heavier and stockier compatriots of grey wolves, with whom they co-existed on the continent before disappearing about 12,000 years ago.

The first cervical vertebra of a dire wolf from the tar pit (left) shows bony growths caused by chronic muscle injury, compared to that of a healthy wolf (right). The spine of a sabertooth cat from the pit (left) likewise displays signs of torsion injuries, compared to the spine of an uninjured saber-tooth. (Photo courtesy Brown et al., Nature)

The jumbled remains of both ancient animals were excavated from a seep of asphaltum — often called tar — known as Pit 61/67 at Los Angeles’ famous La Brea Tar Pits.

(See more science from the tar pits: “Ancient Cougars Survived Ice Age Extinction By Not Being Picky Eaters, Study Finds“)

Numbering more than 35,000 in all, the bones were studied by researchers from UCLA over the course of six months, the first study to determine the frequency of battle injuries sustained by these Ice Age predators.

In the end, just under 2,000 of the bones revealed clear signs of trauma sustained in combat.

And the two predators seem to have routinely suffered separate types of injuries.

Saber-tooth cats, for instance, displayed unusually frequent injuries in the shoulders and lumbar vertebrae, or lower back, while the wolves suffered a higher-than-expected incidence of wounds in the neck and legs.

“The difference in neck injuries between the two animals is dramatic,” said Brown in a press statement.

“The dire wolves had many neck injuries clustered together that could have resulted from the wolves being dragged by thrashing prey, as we see in modern wolves.

“In contrast, the saber-toothed cat has almost no neck or head injury, which implies that they were avoiding damage to their precious teeth.”

These patterns are probably evidence of the different hunting techniques that the predators used, Brown and her colleagues added.

Saber-tooth cats, for example, are thought to have subdued their prey not with their trademark fangs, but with their oversized forelimbs, pulling down their victims in order to deliver a final, fatal bite.

“Consequently, we expected injuries in saber-toothed cats would likely be concentrated in the shoulder, anterior ribcage and spine,” said UCLA biologist Blaire Van Valkenburgh, also in the statement.

Dire wolves, by contrast, hunted by chasing, rather than ambushing, their prey, and they did almost all of their deadly work with their powerful jaws.

“Dire wolves hunted in packs, which were essentially a running set of jaws,” Van Valkenburgh said.

“They had to do everything with their mouths.”

(Discover an obscure animal whose bite was even stronger: “Ancient Predator of the Northern Plains Had Fiercest Bite of Any Mammal Ever, Study Says“)

This not only caused tremendous strain on the muscles and bones of the neck, she said, but it also made the wolves’ forelimbs and rear legs vulnerable to defensive attacks.

In addition, wolves sustained more injury to the skull, again likely reflecting the risks involved in chasing their prey for long periods.

“Head injuries were likely to be more common in the dire wolves, because they were at risk of being kicked while biting the hind quarters during a chase,” Van Valkenburgh noted.

A diagram shows “hot spots” of frequent injuries among the saber-tooth cats (left) and dire wolves (right) found in Pit 61/67. (Image courtesy Brown et al., Nature)

The study also found that saber-tooth cats were more likely overall to have been injured while hunting than their canine counterparts.

About 4.3% of the big cats showed lasting injury, while only 2.8% of the wolves did.

(See another recent discovery of Ice Age fossils: “Cave Discovered in South Dakota Contains Thousands of Ice Age Fossils“)

This may be because saber-tooths tended to attack larger prey, the researchers speculated, and they also hunted alone instead of in packs.

“In conclusion,” the team writes in their study, “there are clear and substantial differences in the distribution and frequency of pathological elements in two large extinct carnivorans, S. fatalis and C. dirus.

“The markedly different distributions probably reflect the distinct hunting modes of these two species, whereas the difference in absolute frequency might be owing to differences in prey sizes and hunting behaviours.”

Brown and her colleagues published their results in the journal Nature Ecology and Evolution.

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