Were Saber-Toothed Cats as Timid as Tabbies?

You might think Smilodon fatalis--commonly, and mistakenly, known as the "saber-toothed tiger"--was a vicious, relentless, unstoppable predator. However, a new study comparing the sizes of male and female Smilodon specimens has reached the opposite conclusion: this prehistoric cat, which prowled the North American plains from 1.5 million to 10,000 years ago, may not have been as aggressive as it's been portrayed in countless Hollywood movies.

The reasoning comes down to this: in populations of modern big cats, like lions and tigers, males are significantly bigger than females, the evolutionary result of having to fight one another for the right to mate. All this sparring and tussling breeds aggression, increased size and greater speed, resulting in male-dominated packs that make short shrift of Savannah wildlife.

The lack of sexual dimorphism in Smilodon, on the other hand, hints at a much more egalitarian pack structure, with a comparable lack of meanness. However, it's important not to take this argument too far: even if saber-toothed cats were much tamer than modern lions and tigers, they were just as dangerous to their prey (which probably included early humans).