Development of on-shore behavior among polar bears (Ursus maritimus) in the southern Beaufort Sea: Inherited or learned?

Abstract

Polar bears (Ursus maritimus) are experiencing rapid and substantial changes to theirenvironment due to global climate change. Polar bears of the southern Beaufort Sea(SB) have historically spent most of the year on the sea ice. However, recent reportsfrom Alaska indicate that the proportion of the SB subpopulation observed on-shoreduring late summer and early fall has increased. Our objective was to investigatewhether this on-shore behavior has developed through genetic inheritance, asociallearning, or through social learning. From 2010 to 2013, genetic data were collectedfrom SB polar bears in the fall via hair snags and remote biopsy darting on-shore andin the spring from captures and remote biopsy darting on the sea ice. Bears werecategorized as either on-shore or off-shore individuals based on their presence onshore during the fall. Levels of genetic relatedness, first-order relatives, mother-offspring pairs, and father-offspring pairs were determined and compared within andbetween the two categories: on-shore versus off-shore. Results suggested transmission of on-shore behavior through either genetic inheritance or social learning asthere was a higher than expected number of first-order relatives exhibiting on-shorebehavior. Genetic relatedness and parentage data analyses were in concurrence withthis finding, but further revealed mother-offspring social learning as the primarymechanism responsible for the development of on-shore behavior. Recognizing thaton-shore behavior among polar bears was predominantly transmitted via sociallearning from mothers to their offspring has implications for future management andconservation as sea ice continues to decline.