In male gay culture, a bear is often a larger, hairier man who projects an image of rugged masculinity. Bears are one of many LGBT communities with events, codes, and a culture-specific identity.
However, in San Francisco in the 70s any hairy man of whatever shape was referred to as a ‘bear’ until the term was appropriated by larger men and other words had to be found to describe hairy other-shaped men such as otter (slim) or wolf (medium-build).
The term bear was popularized by Richard Bulger, who, along with his then partner Chris Nelson (1960–2006) founded Bear Magazine in 1987. There is some contention surrounding whether Bulger originated the term and the subculture’s conventions. George Mazzei wrote an article for The Advocate in 1979 called “Who’s Who in the Zoo?”, that characterized homosexuals as seven types of animals, including bears. The bear concept can function as an identity or an affiliation, and there is ongoing debate in bear communities about what constitutes a bear. Some bears place importance on presenting a clear masculine image and may disdain or shun men who exhibit effeminacy, while others consider acceptance and inclusiveness of all behavioural types to be an important value of the community. Source