The head is small and flattened with large eyes and long eyelashes. The male's back feathers are black with a white tail. 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.