Reproduction and parental care

Southern giraffes courting (above) and mating in Namibia. Generally, only dominant males are able to mate with females.

Reproduction in giraffes 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 oestrus, in a multi-step process known as the flehmen response.^[85][89] Males prefer young adult females over juveniles and older adults.^[85] Once an oestrous female is detected, the male will attempt to court her. When courting, dominant males will keep subordinate ones at bay.^[89] A courting male may lick a female's tail, rest his head and neck on her body or nudge her with his horns. During copulation, the male stands on his hind legs with his head held up and his front legs resting on the female's sides.^[45]

Giraffe gestation lasts 400–460 days, after which a single calf is normally born, although twins occur on rare occasions.^[92] The mother gives birth standing up. The calf emerges head and front legs first, having broken through the fetal membranes, and falls to the ground, severing the umbilical cord.^[7] The mother then grooms the newborn and helps it stand up.^[53]:40 A newborn giraffe is 1.7–2 m (5.6–6.6 ft) tall.^[47][48][49] Within a few hours of birth, the calf can run around and is almost indistinguishable from a one-week-old. However, for the first 1–3 weeks, it spends most of its time hiding;^[93] its coat pattern providing camouflage. The ossicones, which have lain flat while it was in the womb, become erect within a few days.^[45]

Mother Masai giraffe and calves feeding in Kenya. It is mostly the females that raise young, and they may gather in nursery herds.

Mothers with calves will gather in nursery herds, moving or browsing together. Mothers in such a group may sometimes leave their calves with one female while they forage and drink elsewhere. This is known as a "calving pool".^[93] Adult males play almost no role in raising the young,^[40]:337 although they appear to have friendly interactions.^[85] Calves are at risk of predation, and a mother giraffe will stand over her calf and kick at an approaching predator.^[45] Females watching calving pools will only alert their own young if they detect a disturbance, although the others will take notice and follow.^[93]

The length time in which offspring stay with their mother varies, though it can last until the female's next calving.^[93] Likewise, calves may suckle for only a month^[40]:335 or as long as a year.^[45][89] Females become sexually mature when they are four years old, while males become mature at four or five years. Spermatogenesis in male giraffes begins at three to four years of age.^[94] Males must wait until they are at least seven years old to gain the opportunity to mate.^[45][53]:40