In the late Pleistocene period, approximately 11,500 years ago, the area near what’s now downtown Los Angeles was a dangerous place.
Dire wolves – not a “Game of Thrones” invention, but now-extinct predators that were like present-day wolves, but bigger – and sabre-tooth cats chased down or ambushed prey animals in the region, killing bison, horses, and even the calves of mammoths and mastodons.
We know this because the La Brea tar pits in the area hold a treasure trove of the skeletons of these creatures. A recent analysis of thousands of their bones, published in the journal Nature Ecology & Evolution, reveals new details about how those creatures hunted – and about the injuries they suffered while taking down prey.
From just one pit, researchers were able to analyze thousands of bones from hundreds of the predators, which were lured to their deaths in the tar as they ventured onto the treacherous ground, trying to reach prey animals that had become trapped.
So many have been found that staff and researchers who work with the tar pits realized the bones could help tell the stories of these hunts by demonstrating the ways predators were hurt by the animals they hunted.
“It helps us imagine what an ecosystem is like when you have very different types of predators,” says Caitlin Brown, a graduate student at UCLA and lead author of the new study. “We see the way predators may have specialized with different tactics to take down prey.”
Since researchers think dire wolves ran down their meals like modern wolves, Brown says they expected to see significant injuries to the skulls and teeth of the wolves, which would have come from being kicked by their prey.
Surprisingly, these fractures were rare, with cranial injuries found in less than 2% of specimens. But they did find a high proportion of neck injuries, meaning it’s likely the wolves would latch onto their massive prey to drag it down. We see the same injuries in grey wolves today after they sink their teeth into the hindquarters of bison and moose.
The wolves did have leg injuries that match what we’d expect to see in animals that spend their lives on the run. There were signs of ligament and tendon injuries, pulled muscles, and even arthritis. “I’m struck by how relatable a lot of these injuries are,” says Brown.
Sabre-tooth cats (Smilodon fatalis, also known as the sabre-toothed tiger, though it wasn’t closely related to modern tigers), on the other hand, were injured more frequently than wolves. The researchers think this was because they were more likely to be solo predators, taking down those same big animals all on their own.
Sabre-tooth cats, however, seemed to be experts at avoiding injuries to their heads and to those massive teeth they were famous for, which Brown says were actually “somewhat fragile,” since they were long and thin. Instead, the cats had more shoulder and back injuries, which the researchers think came from wrestling their prey to the ground. Once they had their meal pinned down with their forelimbs, they could have used those long teeth to deliver a killing blow to the neck or belly.
It’s perhaps the most accurate picture of a prehistoric hunt we have so far, and one that helps confirm researchers’ suspicions that dire wolves were pursuit predators and the big cats were more likely ambush hunters.
The other surprising thing about these findings, according to Brown, is that it was possible to conduct the study in the first place. The UCLA and La Brea researchers looked at more than 35,000 bones, which came from just two species in one single tar pit. A similarly detailed in-depth analysis of existing predators today would be impossible, since you wouldn’t be able to get access to the same wealth of data.
“Predators today are severely endangered,” says Brown. “If we wanted to do this today, we’d be faced by [the fact of] not having enough samples of modern animals.”