Smilodon's Family Tree, or Pole

Publication Info:

Transcript:

Hugo Schmökel, et al. Foraminal widening indicating a spinal nerve tumor in the saber-tooth cat Smilodon fatalis from Rancho La Brea. Frontiers, Volume 13 - 2026 doi: 10.3389/fvets.2026.1857385

The world famous saber toothed cat may have had a lot not working in its favor toward the end of its reign. Some new research may have found evidence of significant inbreeding within the Smilodon population found at the La Brea Tar Pits!

Episode 317

Notes:

So, the saber-tooth tiger's family tree may look more like a telephone pole. Some background knowledge, a saber-tooth tiger isn't really a great term for it. Smilodon was not a tiger. It wasn't even all that closely related to tigers. And there are multiple saber-tooth cats other than Smilodon. And there are multiple species within the Smilodon genus. That said, the most famous one, the one you're probably picturing as the saber-tooth cat or saber-tooth tiger, is Smilodon fatalis. Part of the reason it's so famous is that so many fossils have been found, especially at the La Brea Tar Pits, where they have just found a ton. For example, they found over 3,700 fossil vertebrae from over 850 individuals. They've obviously found other bones, too, but the vertebrae are what matter the most in this case. And keep that 3,700 number in mind, because new research has found some unfortunate features on the bones, like developmental issues, including 32 incompletely formed arches, 48 fused vertebrae, and a whopping 226 vertebrae that just aren't properly formed. Like, for example, a cervical vertebra in the neck that formed like a thoracic vertebra with a rib. And a rib in your neck just doesn't seem comfortable. Paleontologists also found three different vertebrae from three different individuals, which they know are different individuals cuz they were found in different pits. And all three vertebrae had signs of spinal nerve tumors, which are rare, at least generally. With, for example, humans only having a rate of something like 0.22 to 0.38 out of every 100,000. The La Brea Smilodon population has a rate of over 350 out of every 100,000. According to paleontologists, the mix of this increased tumor rate plus the developmental issues could be an indication that the population was extremely inbred, because similar problems have been observed in gray wolves. This doesn't mean Smilodon went extinct because it was inbred, but that it was most likely inbred because its population had already decreased to a point that wasn't necessarily sustainable. They also want to point out that things like spinal nerve tumors hurt, and these animals couldn't necessarily have hunted normally. Meaning that prey animals stuck in tar pits may have been the only realistic option for these animals to hunt. As usual, if you want more information, here's the source.