American Bison / Buffalo - male (large) and female (smaller) in rut. The bull enters the matriarchal herd and displays 'flehmen' and 'tending behavior'. (Bison bison). Wyoming, USA. Flehmen consists of curling the lip back and extending the neck and is thought to enhance the sense of smell. He 'tends' a female by remaining between her and the herd in an attempt to keep the cow isolated. Inhabits plains - prairies and river valleys and sometimes forests. Grazes on grasses, sedge and forbs.