coast where they are treated and released. The largest of these centers, The Marine Mammal Center Hundreds of California sea lions (Zalophus cali-(TMMC), is located in the Marin County Headlands, fornianus) strand along the Pacific coast of North just north of San Francisco. Veterinarians and vol-America each year. They are treated for a variety unteers at TMMC treat pinnipeds for a variety of of conditions at marine mammal clinics along the diseases, including infection with viral and bacterial coast, including malnutrition, physical trauma, pathogens, malnutrition, physical injury, and expoinfections, and toxicosis. The largest clinic is The sure to neurotoxins. Marine Mammal Center (TMMC) in the Marin Strandings of California sea lions (Zalophus County Headlands just north of San Francisco californianus) often exceed 100 individuals per where sea lions can reside for weeks to months year with occasional years marked by large spikes before release. Assessment of illness and recovery (Greig et al., 2005). Between 2002 and 2012, 5,660 can be difficult. Since healthy sociality is sensi-sea lions were admitted to TMMC, of which 2,139 tive to developmental impairment and illness, were released; 40 recovered but were placed in understanding of typical social interactions would facilities; and 3,408 were either picked up as caraid in the assessment of overall recovery. To gain casses, died on arrival, or were euthanized. A total insight to the social behavior of captive California of 1,256 juveniles were treated at TMMC of which sea lions, we examined the behaviors of recovering 714 died, 532 were released, eight were relocated, immature individuals at TMMC. We found that the and two were placed in facilities. Malnourished sea lions in male pens were generally more physi-juveniles totaled 188 individuals; and during our cally active, expressing more approach interactions study period (July to November 2012), 25 of these and coordinated swimming per day. The sea lions malnourished individuals were treated at TMMC. in mixed-sex pens fluctuated in activity, with the In addition to malnourishment, sea lions come to level of activity decreasing as the day went on; TMMC with injuries from physical trauma; viral while the sea lions in male pens maintained simi-and bacterial pathogens (such as leptospirosis); high lar levels of activity all day. These findings offer a body burdens of anthropogenic compounds (such foundation for more rigorous studies of the social as PCBs and perfluorinated octane sulphonate); or neurobiology of recovering California sea lions. exposure to domoic acid, a neurotoxin produced by algae, most commonly a species of Pseudo-nitzchia

Skull specimens from: southern sea otter (Enhydra lutris nereis), Eastern Pacific harbor seal (Phoca vitulina), California sea lion (Zalophus californianus), northern fur seal (Callorhinus ursinus), walrus (Odobenus rosmarus), polar bear (Ursus maritimus), North American brown bear (Ursus arctos), American black bear (Ursus americanus), California mountain lion (Puma concolor couguar), California bobcat (Lynx rufus californicus), gray fox (Urocyon cinereoargenteus), kit fox (Vulpes macrotis), and gray wolf (Canis lupus) (n = 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 (p < 0.001, p = 0.005, p = 0.005, p = 0.002, and p = 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 p < 0.001), and kit fox (p = 0.001). Gray wolf and American black bear young adults were significantly (p = 0.047 and p < 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 (p < 0.001, p < 0.001, and p = 0.033, respectively). TMJ-OA can lead to morbidity and mortality in wild animals, but its etiology is not yet fully understood.

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