Infanticide or predation? Cannibalism by a brown bear in Hokkaido, Japan

Abstract

Cannibalism in brown bears (Ursus arctos) is infrequently reported worldwide. This study reports evidence of brown bear cannibalism in northern Hokkaido, Japan. In April 2017, we found a bear scat containing the body parts of a bear cub. We also found a series of tracks (width of the front track: 16 cm) of an adult male bear near the scat, which were likely associated with the excrement. The scat was found at the end of a long hibernation season and the beginning of mating season of brown bears in Hokkaido. The timing suggests that the cannibalism event was a consequence of infanticide by a male bear as part of mating strategy, namely, sexually selected infanticide.