Saber-Tooth Cats and Dire Wolves Carried a Terrible Disease in Their Bones
The team discovered that around six percent of the limb bones of young adult and juvenile saber-tooth cats, specifically knee joints, had divots measuring less than seven millimeters.
Nearly three percent of young adult and juvenile dire wolves also had defects in the knee joint that tended to be larger, measuring more than 12 millimeters. Small shoulder joint defects were more common in the wolves, the same as in dogs, totaling almost five percent. A few adult limbs, but no juvenile limbs, showed signs of osteoarthritis, a degenerative joint disease that can result from OCD.
Prevalence of the disease among the animals appeared to be more than among modern animals and humans, Dr. Schmökel said.
Just from bones, it’s unclear why OCD struck the way it did. Nor can the researchers say for sure how it affected the animals’ quality of life or mobility. In modern domestic animals, the disease can cause varying levels of pain and lameness. In early life, these bone defects can heal on their own; it may not have been much of an impairment, at least for some individuals. The animals’ social behavior also may have mitigated the worst of the disease, said Larisa DeSantis, a paleontologist at Vanderbilt University who was not involved in the study.
In an email, she said other specimens from the La Brea Tar Pits had signs of “hip dysplasia and severe arthritis, revealing the ability of these ice age predators to live for an extended period of time with such injuries.”
But to the researchers, the higher prevalence of OCD offers grounds for speculation that there was an inbreeding problem among saber-tooth cats and dire wolves as a result of dwindling, isolated populations. Dr. Schmökel points to modern-day animals like Isle Royale wolves and Florida panthers that have experienced the same.
While Dr. DeSantis is skeptical OCD was solely involved in the extinction of these apex predators, Dr. Balisi says the findings are a prompt for further research.
Signs of the disease, Dr. Balisi said, “could be a morphological manifestation of something deeper that we can’t get to just yet, but I think it’s only a matter of time.”