Saber-Toothed Tigers, Dire Wolves Were Already in Trouble Due to Inbreeding Before Extinction

Saber-toothed tigers and dire wolves were already extinct. However, according to a new report, their population had already struggled due to inbreeding long before becoming extinct.

Saber-Toothed Tigers, Dire Wolves Inbreeding

It's unclear exactly what led to the extinction at this point. The emergence of people and climate warming are two common hypotheses. Inbreeding may have contributed to the saber-tooth tiger and the dire wolf, according to recent research by Hugo Schmökel and his colleagues at the Evidensia Academy, a veterinary institution in Sweden, per The Economist.

According to Britannica, inbreeding refers to the union of people or organisms who are genetically related to one another. Since the combined influence of detrimental genes that were recessive in both parents, inbreeding is generally associated with lower vigor, size, and fertility of the offspring. This is because inbreeding is advantageous in the retention of desirable features or the eradication of undesirable ones.

After inspecting bones from the Rancho La Brea Tar Pits in Los Angeles, Dr. Schmökel came to that conclusion. Because they were death traps for the animals of the time, these were treasure troves for paleontologists. The tar may collect rainwater on top of it. A large herbivore, such as a mastodon or a gigantic sloth that entered for a drink, risked getting caught in the trap.

Predators would be drawn to it and attack it due to its successive attempts to escape, only to get stuck afterward. As a result, Rancho La Brea has thousands of animal bones in it.

This makes it possible to do statistical analyses that are not possible elsewhere. About 834 saber-tooth cat femurs dating from between 12,000 and 10,000 years ago were analyzed by Dr. Schmökel. Approximately 6% of the samples showed abnormalities indicative of osteochondrosis dissecans, a bone disease. This is brought on by tiny pieces of bone beneath the cartilage of a joint decaying and breaking free. In old age, it becomes crippling and results in joint pain and loss of motion. 2.6% of the 266 dire-wolf femurs examined for the study also exhibited disease-related abnormalities.

Diet and trauma are two factors that can contribute to osteochondrosis dissecans. However, genetics is one of the main risk factors.

Even though the illness is now uncommon in wild animals, it is widespread in extensively inbred domestic dog breeds. It affects about 9% of border collies.

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Inbreeding in the Wild

Inbreeding is not always the result of human intervention. In the wild, it typically results from a dwindling population with fewer mates available with each passing generation.

The paper shows that the dire wolves and the saber-toothed tigers were caught in a sad downward spiral long before they became extinct. Their populations were already declining, and the sickness brought on by the ensuing inbreeding would have made it more difficult for the surviving individuals to live, particularly as they became older.

However, why they became inbred in the first place cannot be determined, at least not immediately. According to the tar pit data, they may have been on the verge of extinction long before eventually giving in.