Polar bears (Ursus maritimus) living near the southern Beaufort Sea are spending more time on land during the summer months than in years past as a result of climate change and melting sea ice. Researchers wanted to know whether bears that spent more time on land were exposed to more pathogens compared to those who spent more time on sea ice. Their results, published in the journal Physiological and Biochemical Zoology, showed that bears living on the shore have increased numbers of circulating white blood cells than bears who summered on the sea ice. These findings suggest that bears summering on the shore may indeed be exposed to more pathogens, which may have health implications for the animals.
JP Whiteman, HJ Harlow, GM Durner, EV Regehr, SC Amstrup, M Ben-David. Heightened Immune System Function in Polar Bears Using Terrestrial Habitats. Physiological and Biochemical Zoology, 92(1): 1-11, 2019.