The frightful saber-toothed cats and the terrible wolves are suffering from joint and bone conditions at the close of time, which could indicate that these animals were breeding when they went extinct.

Researchers have studied the animal’s bones at the close of the last glacial period in the Pleistocene period (about one thousand years old) to understand the ecology present in North America better when these two predators disappeared.

“They seem so big and fearsome,” However, this evidence of disease could suggest that saber-toothed cats as well as dire Wolf “were going through tough times,” study co-author Mairin Balisi, who is a paleontologist at the Raymond M. Alf Museum of Paleontology in California she told Live Science.

In the last days of the most recent ice age, the region that is currently Los Angeles was home to an entire ecosystem of gigantic mammals that defined the period, including Columbian mammoths ( Mammuthus columbi), Jefferson’s ground slots ( Megalonyx Jefferson) and the earliest bison ( Bison antiquus). The highest of the food chain was the most formidable carnivores, such as saber-toothe cat ( Smilodon fatalis) and dire wolves ( Aenocyon dirus).

A few of the animals met an uneasy end when they fell to the La Brea pits of tar – natural bubbling pools of asphalt located just south of the area that is today West Hollywood. Their remains were buried within the holes and then excavated by paleontologists.

The researchers looked at hundreds of saber-toothed cats and dire wolf bones to search for signs of a disorder known as osteochondrosis dissecans (OCD) that occurs when bone defects develop in joints. OCD can be found in cats, dogs, and humans, increasing the likelihood of developing osteoarthritis. This is a painful joint disorder.

Balisi stated that they didn’t expect to find any indications of OCD in carnivores since there’s not much information on joint and bone diseases in modern wild animals. However, 6% of the femurs of saber-toothed cats they looked at had noticeable imperfections. In the wolf population that was in dire need, 2.6% of their femurs, as well as 4.5 percent of their shoulders, showed defects.

The majority of defects were small. However, some were larger, and some had indications of arthritis, like bone growth. Researchers published their findings on Wednesday (July 12, 2013) by publishing their results in PLOS One.

Being able to see these kinds of illnesses in the fossil record is “really interesting, because it gives us this sort of holistic look at how these things evolve, and how they might change over time,” Ashley Reynolds, an evolutionary ecologist from the University of Ottawa and the Canadian Museum of Nature, who wasn’t involved in the new study said to Live Science.

Bone and joint health are likely to be crucial for the ability of predators to hunt, Balisi said. While this illness could cause problems when hunting, animals that were part of the study died from the tar pit, not because they had stopped hunting, but instead were starving to death, according to Balisi. Additionally, although there’s a debate over the social nature of saber-toothed animals, these animals who suffered injuries could likely have lasted longer sharing food with other animals.

The researchers speculate that the animal may be suffering from the effects of inbreeding as their numbers declined and moved closer to eventual death- dogs who suffer from OCD tend to be inbred, they noted. Since these giants of the ice age became isolated geographically from each other, their inbreeding rates could have increased; because inbreeding causes an increase in the incidence of inherited diseases, OCD may have become more common as their death was getting closer.

However, no genetic evidence has been preserved within the pits to prove this hypothesis directly. Reynolds stated that she would be interested to determine whether OCD is also a problem in wild animals of the present that have experienced interbreeding, like cheetahs.