Dissecting the Cave Lion Diet

To figure out what these lions hunted, biogeologist Hervé Bocherens and colleagues at the University of Tübingen in Germany, analyzed bone samples from 14 cave lions—found in four caves in France and central Europe—that lived between 12,000 and 40,000 years ago. The team focused on the chemical content of the bone collagen, which is often well-preserved, even in bones tens of thousands of years old. By incinerating a tiny fragment of preserved bone—usually less than a milligram—researchers can identify the molecules inside it and determine an animal's diet.

Scientists have perfected the technique over the years. It was used recently to look at the diet of Neandertals, but this is one of the first studies to use it to look at a nonhuman predator—and the analysis is now sensitive enough to look several steps down the food chain. This enabled Bocherens to determine not only what cave lions ate but also what their prey ate. And that made it possible to tell, for example, whether lions were targeting full-size cave bears or their more vulnerable cubs, because adults and babies eat different diets themselves. "There's a difference between the [chemical] signal of adults and babies," Bocherens says. "Babies drink the milk of the mother."

As it turned out, this distinction was important. Bocherens's analysis, reported in the 6 December issue ofQuaternary International, revealed that the cave lions occasionally ate bear cubs but not adults. Their favorite food, however, was reindeer, which Bocherens and his team determined consumed massive quantities of lichen, much as their modern descendants did. The cave lion diet, Bocherens says, appears to have been much more finicky than that of today's lions, which eat just about anything they can catch.