Inbreeding and Mobility Issues Doomed Saber-Toothed Cats Before Extinction
Saber-toothed cats became inbred–and struggled to move–before they went extinct
New research on Smilodon fatalis fossils from the La Brea Tar Pits reveals that population decline led to severe inbreeding. This genetic bottleneck caused a spike in spinal deformities and rare nerve tumors, crippling the cats' mobility. These physical ailments likely forced them to rely on trapped prey, accelerating their demise just before the end of the last ice age.
Your population's decreasing, and that leads to inbreeding, which makes you less able to respond to any kind of perturbation because you're losing that genetic diversity that evolution can play with.
- conductr
If you watch predator behavior, they will always go for an easy kill. The tar pit provides those opportunities. Also, if these opportunities are routine enough and occur in a hyper local area, it’s hardly even hunting they become more like scavengers patrolling the area and perhaps defending it from competition.
That said, it seems more likely to me cats near the tar pits just held the territory and became inbred from that. You can see similar patterns today around a junk yard. There will be feral dogs or cats that are living off the trash. They protect it from outsiders and inbreed.
That’s if inbred is even the explanation. I think it’s also possible that weak or deformed cats may just prefer this site more than healthy cats as they are hungry enough to take the risk. So the population bias is inherently there through attendance. If cats are getting stuck in tar so frequently, it’s likely they knew going near it was risky. Healthy cats would hunt elsewhere and avoid the risk.
- litoE
Wouldn't it make sense to assume that as the size of the population decreases, perhaps for external factors such as climate change, you are going to see more and more inbreeding?
- chrisco255
I think the study makes a giant presumptive leap to assume inbreeding was the cause of the higher-than-modern-human incidences of spinal tumors. It's irresponsible to assert this to be true instead of one of several possible explanations.
- NL807
I was always puzzled how these cats actually fed. These sabre toots seem to get in the way of feeding and chewing.
- Animats
Another predator that went through a genetic choke point. Cheetahs did, too.[1]
Cheetahs survived, but they are so similar genetically that they get the same illnesses, and skin grafts between unrelated cheetahs are not rejected.
[1] https://academic.oup.com/jhered/article/108/6/671/3836924