The female, or hen, is duller with grayish-brown coloring. Ostriches have lived 50 years in captivity. They are polygamous, mating with three to five hens. Males build the nest. All the hens share a common nest.
Eggs weigh about three pounds each and have a very hard, glazed, cream-colored shell.
One female, called the alpha female, becomes dominant and incubates the eggs during the day while the male incubates at night. They can incubate only 20-22 eggs each time. The alpha female discards excess eggs, but she can recognize her own eggs and always incubates them. Incubation lasts about 42 days. The eggs hatch in October and November.