New findings have determined that long before saber-toothed tigers and dire wolves became extinct, their population was struggling with a bone and joint disease, an indication that they may have been inbreeding.
Scientists came to this conclusion after inspecting bones from the La Brea tar pits in Los Angeles. Many animals were drawn to the tar pits as the tar would often collect rainwater on top of it. Those who went in for a drink would sometimes fall into the pits and get stuck.
As a result, the tar pits are treasure troves for paleontologists since thousands of animal bones have been preserved in the pits.
After analyzing hundreds of saber-toothed tiger and dire wolf bones for a bone disease called osteochondrosis dissecans (OCD), researchers found that approximately six percent of the saber-toothed cats’ femurs showed signs of defects.
Additionally, 2.6 percent of the dire wolves’ femurs exhibited abnormalities related to the bone disease. OCD is brought on when small pieces of bone beneath the cartilage of a joint break down.
OCD can occur in modern dogs, cats, and humans. It can also increase the risk of developing osteoarthritis.
The illness is especially common in domestic dog breeds that have been extensively inbred. Nine percent of border collies are affected by OCD.
So, the presence of the disease in the fossilized remains seems to indicate that the species were suffering from inbreeding. In the wild, inbreeding typically is a result of a dwindling population.
As the species grew more isolated from one another and the number of available mates decreased due to the last ice age, it is likely that inbreeding rates went up. Therefore, OCD became more prevalent toward the end of their existence.