A male moose is called a bull, while a female moose is called a cow. A baby moose is called a calf. Both male and female moose have a dewlap or bell, which is a fold of skin under the chin. Its exact function is unknown, but some morphologic analyses suggest a cooling (thermoregulatory) function. Other theories include a fitness signal in mating, as a visual and olfactory signal, or as a dominance signal by males, as are the antlers.