Incisor analysis technique to predict the gender of black bears damaging trees

Black bear (Ursus americanus) feeding on tree cambium is a forest management concern in the Pacific Northwest. Predicting the gender of bears foraging on cambium could provide valuable insight for damage management by focusing management on depredating bears. Equations were generated from dental impressions taken from live bears captured in western Washington State to classify the gender of bears that left incisor grooves on freshly damaged trees. Males had wider primary, I1, (0.55 cm±0.01, P=0.04) and secondary, I2, upper incisors (0.67 cm±0.01, P=0.001) than female bears (0.49 cm±0.02 and 0.58 cm±0.01, respectively). The widths of individual incisor grooves in the cambium of trees in western Washington were measured and compared to dental measurements from live bears, revealing that females damaged 90% (88 of 98 trees with I1 impressions; 66 of 73 trees with I2 impressions) of trees sampled during 1996. Damage management programs should target female bears rather than indiscriminately applied to all bear age-gender classes.