This is consistent from what has been observed of Smilodon skulls and skeletons, though more examinations will be required to further test the hypothesis the authors of this latest paper have proposed. With one possible exception, there were distinct clusters and males and females divided by an intermediate gap that was not occupied. As Meachen-Samuels and Binder note in the paper, as big cats age the pulp cavity inside the canine tooth becomes increasingly infilled with dentin. Hence the amount of tooth wear seen in an individual jaw can be deceptive, but the authors of the new study found a different way to estimate the age of the fossil cats. As might be expected the measurements from the fossil lions fell into two separate groups, just like modern lions, with the larger individuals probably being males and the smaller ones being females. But what does this say about social systems of the La Brea lions and Smilodon? With this technique the authors could then compare the amount of dentine in the teeth to the size of the lower jaw, this latter measurement being used to indicate overall body size in each of the three species being examined.
Hallie. Age: 21.
The older the animal is, the more filled that pulp cavity is.
Kallie. Age: 31.
No such pattern was seen among the data from Smilodon. With this technique the authors could then compare the amount of dentine in the teeth to the size of the lower jaw, this latter measurement being used to indicate overall body size in each of the three species being examined. Previous studies used tooth wear to determine approximate ages of fossil carnivores from La Brea. In Smilodon the hypothesized males and females all clustered closely together and did not separate out into two distinct groups.