Ursinae is a subfamily of Ursidae (bears) named by Swainson (1835) though probably named before Hunt 1998. It was assigned to Ursidae by Bjork (1970), Hunt (1998) and Jin et al. (2007).
The genera Melursus and Helarctos are sometimes also included in Ursus. The Asiatic black bear and the polar bear used to be placed in their own genera, Selenarctos and Thalarctos; these are now placed at subgenus rank.
A number of hybrids have been bred between American black, brown, and polar bears (see Ursid hybrids).
^Bjork, Philip R. (1970). "The Carnivora of the Hagerman Local Fauna (Late Pliocene) of Southwestern Idaho". Transactions of the American Philosophical Society. American Philosophical Society. 60 (7): 3-54. JSTOR1006119.
^Hunt, R. M. (1998). "Ursidae". In Jacobs, Louis; Janis, Christine M.; Scott, Kathleen L. (eds.). Evolution of Tertiary Mammals of North America: Volume 1, Terrestrial Carnivores, Ungulates, and Ungulate like Mammals. Cambridge, UK: Cambridge University Press. pp. 174-195. ISBN0-521-35519-2.