Cougars are one of the only big cats to survive past the end of the last Ice Age in the U.S. Other big cats, such as the American Lion and saber-toothed cat, went extinct roughly 12,000 years ago. Researchers now have an idea of why cougars survived when other cats didn't.
According to an article on the website Science Daily, researchers studied the microscopic wear marks on the teeth of cougars, American lions and saber-toothed cats, and found that cougars had a far more diverse diet. The other big cat to survive was the jaguar, which is now, sadly, considered near threatened due to human influence.
The wear patterns on the teeth of the American lion are very close to what's found on the teeth of modern cheetahs. Cheetahs, the researchers noted, are very, very finicky eaters. They rarely consume anything other than tender meat, and almost never chew bone. Saber-toothed cats consumed both meat and bone, but not likely entire carcasses.
The wear patterns on the teeth of cougars, on the other hand, are closer to what's typical for the modern hyena. In fact, while cougars prefer to prey on deer, they'll eat anything from grasshoppers to elk. They'll usually eat the entire carcass of their smaller prey. However, if they're hungry enough, they'll move into human-inhabited areas and eat pet food, or even garbage.
An important fact to note is that the cougar's varied diet also protects certain species from over-predation. Cougars may prefer deer, but aren't likely to destroy an entire deer population if there is other prey around. Also, since cougars are predators, they have a very important ecological role; they keep deer populations in check. Designating cougars "nuisance animals" and killing them has led to overpopulation of their natural prey in some areas of the U.S.
Their hunting and eating behavior could have acted as a buffer against the mass extinction from 12,000 years ago. Not only did they consume more of their prey than their cousins did, which might have led to needing to hunt less, but they also had a wider variety of prey in their diet. So, as some prey went extinct, they were able to adapt by hunting other prey.
It's not known yet whether cougars adopted this strategy in response to the changing environment, or if they already lived this way. Regardless, there is evidence suggesting their diet might be the reason they're alive here today.