Fearsome sabre-toothed cats may have had a tender side. The prehistoric predators risked damaging their powerful jaws and teeth during hunts, but a study of their fossils suggests injured individuals could then rely on their peers for food.
Urban Los Angeles is home to the tar pits at Rancho La Brea. For most of the last 40,000 years, sticky tar has trapped and preserved animals wandering across this landscape, providing a window into the animals of the Pleistocene period.
What’s really special about these tar pits, says Larisa DeSantis at Vanderbilt University in Tennessee, is that it particularly preserved top predators. Because apex predators tend to be few in number, fossils of animals that top the food chain are usually very rare. But the tar pits acted almost like fly paper for predators: they were attracted by the distress calls of trapped herbivores and then got caught themselves.
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So many sabre-toothed cat (Smilodon) fossils have been pulled from the tar that DeSantis and her colleague, Christopher Shaw at the George C. Page Museum of La Brea Discoveries in Los Angeles, have been able to begin to understand how these animals lived.
Shared meals
The two researchers compared 21 Smilodon skulls that showed sign of jaw injuries with 135 skulls that looked uninjured. They found that the pattern of pits and scratches on teeth in the uninjured jaws looks like that seen on the teeth of living lions. The pattern on injured jaws was more like that seen on the teeth of living cheetahs.
That tells us something about the prehistoric cats’ diets, says DeSantis. “Lions are generalised feeders, they eat flesh and bone,” she says. “But cheetahs tend to avoid bone.”
In other words, it seems that Smilodon usually crunched its way through entire carcasses, bones and all, but that once individuals sustained an injury to the jaw they switched to a softer, easier-to-eat diet.
DeSantis argues that this suggests Smilodon was a social animal, with healthy cats letting injured individuals share their kills. The pair at an annual meeting of the Geological Society of America in Indianapolis on Monday.
Sociable cats
However, their social theory assumes that sabre-toothed cats with injured jaws were unable to take down prey. A study published by Blaire Van Valkenburgh at the University of California, Los Angeles, and his colleagues suggests that may not have been the case.
Van Valkenburgh’s team compared fossils of a couple of kinds of sabre-toothed cats, including Smilodon. Their work showed that , which could deliver lethal stabbing wounds. But Van Valkenburgh points out that the cat also had strong forelimbs and paws to hold struggling prey. He suspects individuals with jaw injuries might still have had some ability to kill their own prey.
DeSantis and Shaw’s idea also assumes that Smilodon was a social cat – an idea that has been . But , Shaw presented fossil evidence from the La Brea tar pits that indicates Smilodon could roar like modern lions. This suggests communication was important for Smilodon, adding further evidence that it was a social animal, he says.
Living with injury
“As the decades have passed, I think that people have begun to abandon the idea that all sabre-toothed carnivores were solitary animals,” says Shaw. “Some of these injuries were so severe that injured animals would have benefited from living in a social group that nurtured injured members and provided food and protection.”
This is not the first time that palaeontologists have used fossils from the La Brea tar pits to argue for a form of prehistoric social care. In 2015, a different team looked at a timber wolf thigh bone pulled from the tar. The bone seems to have belonged to a wolf that lost the lower portion of its leg but survived the amputation. The this might hint that the animal stayed alive by eating from kills made by other pack members.
Stuart Sumida at California State University worked on this wolf study. He says the new Smilodon research has been done carefully, and shows that sabretooth cats were not killed by their injuries but instead lived with them. “It gives a much richer picture of survival and biology during the animals’ lives.”
