Giraffe - Behavior and Ecology - Social Life and Breeding Habits

Social Life and Breeding Habits

While giraffes are usually found in groups, the composition of these groups tends to be open and ever-changing. They have few strong social bonds, and aggregations usually change members every few hours. For research purposes, a "group" has been defined as "a collection of individuals that are less than a kilometre apart and moving in the same general direction." The number of giraffes in a group can range up to 32 individuals. The most stable giraffe groups are those made of mothers and their young, which can last weeks or months. Social cohesion in these groups is maintained by the bonds formed between calves. Mixed-sex groups made of adult females and young males are also known to occur. Subadult males are particularly social and will engage in playfights. However, as they get older males become more solitary. Giraffes are not territorial, but they have home ranges. Male giraffes occasionally wander far from areas that they normally frequent.

Reproduction is broadly polygamous: a few older males mate with the fertile females. Male giraffes assess female fertility by tasting the female's urine to detect estrus, in a multi-step process known as the Flehmen response. Males prefer young adult females over juveniles and older adults. Once an estrous female is detected, the male will attempt to court her. When courting, dominant males will keep subordinate ones at bay. During copulation, the male stands on its hind legs with its head held up and its front legs resting on the female's sides.

Although generally quiet and non-vocal, giraffes have been heard to communicate using various sounds. During courtship, males emit loud coughs. Females call their young by bellowing. Calves will emit snorts, bleats, mooing and mewing sounds. Giraffes also snore, hiss, moan and make flute-like sounds, and they communicate over long distances using infrasound.