A Case Study of Respiratory Rates in a Geriatric Polar Bear (Ursus maritimus) With Heart Disease

Respiratory rate data are of interest in marine mammals due to their reliance on living in a marine environment. Polar bears (Ursus maritimus), the most terrestrial of the marine mammals, are considered old bears, or geriatric, when they reach their twenties. Current accepted and utilized respiratory rate information on polar bears were studied on subadult and adult polar bears, with little to no information on geriatric bears. As marine mammals in managed care facilities are outliving their wild counterparts, there is now a population of geriatric animals that there is very little data on in regard to expectations for vitals. This study compared the resting respiratory rate of the geriatric polar bear at the Pittsburgh Zoo & Aquarium to a scale of respiratory rates between terrestrial and marine mammals in subadult and adult age classes. This study also classified any significant differences in respiratory rate between different activity levels the polar bear exhibits on a regular basis. Respiration rates were collected observationally, which was the most easily accessible, non-invasive, and easily repeatable method of collection. The average resting respiratory rate (24.7 ± 11.8 breaths per minute) of the polar bear was not significantly different than the expected values from the scale created with data from subadults and adults. The active respiratory rate was two times higher than the resting respiratory rate, which was statistically significant. There was also a significant difference in the respiratory rate between each behavior exhibited during the observation period. The behavior with the highest respiratory rate was standing (51.9 ± 9.9 breaths per min), which was over four times higher than the behavior with the lowest respiratory rate, sleeping. Sitting (38.3 ± 13.0 breaths per min) was 1.5 times higher than the respiratory rate of laying and 3 times higher than sleeping. The keeper and veterinary teams at the Pittsburgh Zoo & Aquarium will be able to use the analyses for comparing future respiratory rates, which will help to provide continued insight into the polar bear's heart health.