The unexplored maternity dens survey of the polar bear (Ursus maritimus) on Wrangel and Herald islands in 1982

A rare survey of polar bear (Ursus maritimus) maternity dens on Wrangel and Herald Islands, conducted in 1982, revealed key insights into the species' reproductive behavior. Researchers documented 139 dens and sighted 57 bears, with an average of 1.43 offspring per den on Wrangel Island (WI) and 1.86 on Herald Island (HI), occasionally reaching three cubs. The study also highlighted unusual den structures, including one with a complex corridor and another featuring a 4.5-meter vertical tunnel, challenging traditional linear measurements of dens. Additionally, it noted that females typically occupied dens for 6 days but could stay up to 14 days, with the highest frequency of den openings occurring on March 27–28. The research also reported four cases of cub mortality and provided recommendations for improving polar bear survey techniques. This Ukrainian-language publication contributes valuable data to Arctic mammalogy and ecological studies.

Prydatko-Dolin, V. (2022). The unexplored maternity dens survey of the polar bear (Ursus maritimus) on Wrangel and Herald islands in 1982. Theriologia Ukrainica, 2022(24), 184–209. https://doi.org/10.15407/tu2416