Female giraffes can become pregnant at 5 years old. They carry a baby for 15 months and give birth while standing up. Newborns are about 2 m (6 ft.) tall and weigh 70 kg (150 lb.).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.