Among the many puzzles posed by the massive extinction of mammals at the end of the last Ice Age is why North America’s saber-tooth cats and great native lions disappeared, while their equally ancient cousins, the cougars — also known as mountain lions or pumas — continued to thrive.
A new study of big-cat remains found in California’s La Brea Tar Pits may have found an answer, or at least a clue to one: Cougars may have endured simply because they were less picky eaters.
“Before the Late Pleistocene extinction, six species of large cats roamed the plains and forests of North America. Only two – the cougar and jaguar – survived,” said Dr. Larisa R.G. DeSantis, an environmental scientist at Vanderbilt University, in a statement.
“The goal of our study was to examine the possibility that dietary factors can explain the cougar’s survival.”
DeSantis and her colleague, Ryan Haupt of the University of Wyoming, analyzed 50 teeth from ancient cougars, American lions and saber-tooths from Los Angeles’ famous La Brea formation, and compared them with teeth from modern predators.
The researchers looked for microscopic patterns on the teeth that reveal animals’ eating habits — more selective diets of tender meat, for instance, leaving only small scrapes on the tooth enamel, while less discriminating, bone-crunching eating habits caused deeper gouges.
The results showed that cougars had significantly more varied diets than either of their big-cat contemporaries.
Saber-tooth cats, for instance, showed evidence of eating mostly meat with the occasional gnashing on bones, much like modern African lions. [Learn about the evolution of saber-tooths: “America’s Saber-Toothed Cats Weren’t ‘Native,’ Study Finds“]
The extinct American lions, meanwhile, turned out to be as finicky as house cats — their teeth closely resembling those of today’s cheetahs, which dine almost exclusively on tender meat.
The La Brea cougars, however, displayed a much greater variation in patterns.
Some specimens showed the more delicate wear of a mostly-meat diet, while others revealed very heavy wear, similar to that found in hyenas, which are known to consume nearly their entire prey, bones and all.
“This suggests that the Pleistocene cougars had a more generalized dietary behavior,” DeSantis said.
“Specifically, they likely killed and often fully consumed their prey, more so than the large cats that went extinct.”
The scientists note that their findings appear to be reinforced by the behavior observed in modern cougars, which both hunt for prey and scavenge on carrion, often consuming whole carcasses.
So, 12,000 years ago, as the last Ice Age was beginning to thaw and humans were on the hunt, such promiscuous feeding by cougars “may have actually been a key to their survival,” DeSantis said.
The pair published their findings in the latest issue of the journal Biology Letters.