"Male Sabertoothed Cats Were Pussycats Compared to Macho Lions"

We remember sabertoothed tigers as being badass. I mean they had to be, they had awesome fangs and it had a Power Ranger!

However, science might be telling us that TV lied to us. Analysis of fossils of sabertoothed tigers and American lion may suggest that the tiger wasn't as aggressive as we thought.

As discussed in an earlier post, sexual dimorphism is common in many species. In the case of the prehistoric American lion, males were much bigger than females. However, tigers appeared to be the same size regardless of sex. Since neither cat exists today, how did scientists figure this out?

Fossils. And teeth. Although, you can easily sort fossils into groups based on size you have to consider that the animal grows over time. A bone from a young male could be the same size as an older females. Instead, researchers x-rayed the lower teeth and jaw of American lions and sabertooths. As the cats grow, their hollow teeth become filled with dentin, giving an estimated age.

By plotting tooth cavity diameter and jaw length for both species, it was obvious that the size fell into two groups, regardless of age. There was clear evidence for sexual dimorphism--that the bigger teeth were male and the smaller ones were female. However, the tigers sizes were only based on age--that "males were indistinguishable from their mates."

What does that mean?

Well, there needs to be a evolutionary reason for having bigger males. Bigger males can compete and battle better than smaller ones for resources and females. So if the American lion had big males, then they were more aggressive in competition. Scientists theorized that the lions had 1-2 male-dominated groups of females. The sabertooth tiger, instead shows no real difference in size, suggesting that the males and females existed more equally with no reason for aggression.

Duke University (2009, November 5). Male Sabertoothed Cats Were Pussycats Compared To Macho Lions. ScienceDaily. Retrieved November 5, 2009, from http://www.sciencedaily.com/releases/2009/11/091105121050.htm