Temporomandibular Joint Pathology of Wild Carnivores in the Western USA.

Skull specimens from: southern sea otter (), Eastern Pacific harbor seal (, California sea lion (, northern fur seal (), walrus (), polar bear (, North American brown bear (, American black bear , California mountain lion (), California bobcat (, gray fox (, kit fox (, and gray wolf ( ( = 5,011) were macroscopically examined for dental and temporomandibular joint (TMJ) pathology. The presence of temporomandibular joint osteoarthritis (TMJ-OA) varied across species: 4.1% of southern sea otter, 34.5% of harbor seal, 85.5% of California sea lion, 20% of northern fur seal, 60.5% of walrus, 9.2% of polar bear, 13.2% of North American brown bear, 50% of American black bear, 20.9% of California mountain lion, 0% of California bobcat and gray fox, 6.3% of kit fox, and 11.6% of gray wolf specimens had lesions consistent with TMJ-OA. TMJ-OA was significantly more prevalent in males than females in walrus, North American brown bear, polar bear, American black bear, and California mountain lion ( < 0.001, = 0.005, = 0.005, = 0.002, and = 0.004, respectively). No other species showed a sex predilection. Adult specimens were significantly more affected with TMJ-OA than young adults in the harbor seal, fur seal, walrus (all < 0.001), and kit fox ( = 0.001). Gray wolf and American black bear young adults were significantly ( = 0.047 and < 0.001) more affected by TMJ-OA than adults. Of the 13 species analyzed, only three species, namely the harbor seal, northern fur seal, and polar bear, had a significant increase in the prevalence of TMJ-OA if their teeth had attrition and abrasion ( < 0.001, < 0.001, and = 0.033, respectively). TMJ-OA can lead to morbidity and mortality in wild animals, but its etiology is not yet fully understood.