Dental and temporomandibular joint pathology of the North American river otter (Lontra canadensis)

Museum skull specimens from 165 North American river otters (Lontra canadensis) from Alaska, USA, were analysed systematically using an established protocol designed for examination of mammalian dentition. The study population was collected from 1956 to 2012 and comprised a similar proportion of males (n = 82, 49.7%) and females (n = 72, 43.6%). Eleven animals were of unknown sex. The study group incorporated a higher proportion of skeletally mature adults (n = 128, 78.5%) compared to young adults. As with many other mammalian species, the most common types of pathology in this species were periodontitis (n = 158, 95.7%), attrition/abrasion (n = 160, 92.7%) and tooth fractures (n = 87, 52.7%). The North American river otter also had a relatively high prevalence of periapical lesions (n = 41, 24.8%) and root number variation (n = 98, 59.4%) when compared with other mammalian species. Temporomandibular joint pathology occurred at a similar rate to that of the closely related southern sea otter (Enhydra lutris nereis) but most cases were mild in severity.