Tree rubbing by Asian black bears (Ursus thibetanus) in conifer plantations in Okutama Mountain in Japan

Tree rubbing by bears is a well-known behavior, but the behavior has not been investigated systematically in Asian black bears. We installed automatic cameras at trees in planted conifer forests to visually document rubbing behavior and to compare the findings with the results of earlier studies. All trees with bear hair attached had bark damaged from antler sharpening by deer and had secreted resin. Between 2011 and 2015, tree rubbing was observed at five of the 16 trees at which automatic cameras had been installed, with a total of 22 visits by multiple bears. Rubbing was observed from May to October. In the 22 visits, several bears with several attributes (adult male, another male, and mother with cub) visited the same trees to rub them. In our survey, the number of observational confirmations was limited, therefore in order to investigate the factors of Asian black bear's tree-rubbing behavior and determine whether it is the same as in other bears or not, it is desirable to collect further examples of rubbing behavior as well as genetic information of the rubbing individual.