Scientists from Japanese institutions among Tokyo University of Agriculture and Technology (TUAT), Picchio Wildlife Research Center, National Agriculture and Food Research Organization, and Tokyo University of Agriculture have discovered that width of surface layers coating tooth’s roots correlates with reproductive histories of female Asian black bears. When a female bear raised cubs, the layers of her teeth were much narrower compared to those when she was not. Thus, measuring layer width of female bears’ teeth can be a useful index for their reproductive histories. This research was published online in the journal Mammal Study.