Why do females of African ostriches hatch alien chicks

African ostriches form families of several birds, which consist of one male and several females. Despite the apparent equality, one of the females must stand out among her friends. This is the dominant female, which has several advantages. But at the same time, there is a surprising, at first glance, picture: this female hatches not only her eggs, but also the eggs of her competitors. But why does she spend her time and risk being harmed by predators by doing this?

Ostriches live in open spaces and, as everyone knows, do not know how to fly. But adult birds run perfectly and, if necessary, can strike with their powerful legs, so predators are not afraid of them. But their offspring are completely defenseless against hyenas, jackals and birds of prey, which means that breeding and subsequent rearing of chicks requires incredible efforts from these birds.

Ostriches living in the desert and semi-desert are most vulnerable to weather conditions. The appearance of the chicks must exactly coincide with the beginning of the rainy season, otherwise young ostriches simply cannot survive. During the breeding season, the male digs a large hole right in the sand, in the middle of low bushes and islets of grass. The future nest is not protected from attack by predators, but ostriches have no other options. After the nest is ready, all the ostrich harem females lay their eggs there, including the dominant female. Only two are engaged in hatching, regardless of how many females are in the bird family: a male and a dominant female. Hatching and protecting eggs is not an easy task, so an ostrich family simply cannot afford several nests. The father of future offspring sits on eggs at night, and during the day he is replaced by a female. And if during the day the eggs often lie simply in the sand, warmed by the rays of the African sun, and the female allows herself to go away, then the male is in the nest from evening to morning. The air temperature in the desert often approaches 0ºС, and it is simply impossible to leave eggs at this temperature.

But after everyone has laid their eggs, the main female carries out a kind of inventory in the nest, which can contain up to 50 eggs. She recognizes her among many eggs (scientists believe that she distinguishes eggs by the color and pattern of the shell) and rolls them to the center of the masonry. Only after that she sits in the nest, and the position of the eggs does not change anymore, parents only occasionally turn the eggs over to evenly warm and distribute the nutrients inside. The central eggs are in a better position. They do not cool down at night, and a jackal that suddenly descends will never grab an egg from the middle, he can take only one egg and take it from the edge of the nest. Thus, the main female saves her offspring by placing her eggs in the middle, while the eggs of other females are very vulnerable. When the ostriches begin to hatch, it often turns out that no one is hatching from the extreme eggs or weak non-viable chicks appear.