The average male saber-toothed cat was only slightly larger in overall body size than a female saber-tooth, but they had significantly larger mandibles and upper canines (the fangs). This is in contrast to most species of cats today. Most male cats and especially lions are much larger than the average female of their species. The mating habits of Smilodon are completely unknown, and we can only speculate about them based on the knowledge that they differed in size above the neck, but not much elsewhere aside from the sexual organs.
Smilodon had low sexual dimorphism in body size, but males had significantly larger mandibles and upper canines. Did males share their larger kills with females as way to attract them?
I believe saber-tooth mating habits may have been notably different from those of all extant species of cats. The saber-toothed and the scimitar-toothed cats ( Dinobastis or Homotherium ) belonged to an extinct subfamily of cats known as the Machairodontinae. The Machariodontinae diverged from all other cats an estimated 13 million years ago, very early in cat evolution, and they have no close living relatives today. They were more closely related to other carnivores than modern day species of cats are. Perhaps they lived in matriarchal societies like the spotted hyena ( Crocuta crocuta ), another species that shows low sexual dimorphism (the females are actually slightly larger than the males). Or maybe, as in the wolf ( Canis lupus ) only the dominant male and female of the pack were allowed to mate. However, scientists disagree over whether saber-toothed cats were social or solitary animals.
Some scientists argue evidence from the La Brea Tar Pits of severely injured saber-tooths that survived traumatic debilitating injuries suggests they must have lived in groups. But others believe that even a severely injured saber-tooth could have lived for a long time by scavenging. A saber-tooth in a bad mood due to pain could have easily intimidated smaller predators from their kills. Moreover, their small braincases also indicates they didn’t live in groups. I suspect they were solitary cats, though mothers probably hunted cooperatively with nearly grown cubs when she was training them how to hunt.
The males were able to bring down larger prey than the females because their bites, aided by the larger jaws and fangs, were deadlier. Perhaps this was an element of their mating system. Females that came to scavenge the male-killed prey were tolerated by the males, and the heavy meal caused them to go into instant heat. Maybe females followed the most successful hunting males with the frequent nutritious meals triggering more frequent ovulation.
I’ve always been fascinated over how recently this strange exotic animal became extinct–only ~10,000 years ago. It’s frustrating not to be able to know more about how it lived. Relying on guesswork is just not as satisfying as knowing.
Christiansen, P.; and John Harris
“Variation in Craniomandibular Morphology and Sexual Dimorphism in Pantherines and the Sabercat Smilodon fatalis”
Plos One Oct 2012
Meachen-Samuels; J.A.; W.J. Binder
“Sexual Dimorphism and Ontogenetic Growth in the American Lion and Sabertoothed Cat from Rancho La Brea”
Journal of Zoology 2010