Before the birth of pelicans

1991/02/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Zoologia

When the embryos are too hot or cold, they start chioting inside the egg until the parents do something.

Roger Evans, from the University of Manitoba, studied the "American pelican". The female lays in the nest two eggs that are heated with the membranes of her feet.

During the incubation period, adults carefully care for eggs when there is a lot of cold putting them on or off when the sun blows hard. But when a small pelican comes out of the first egg, parents focus on the newborn and the other regulation is not taken care of as much.

When the embryo breaks the skin of the egg a little, the parents change position. In this way they are placed with the egg between the legs and meanwhile the second is left uncared. Therefore, it remains unprotected from both cold and sun.

The second embryo present in the egg is unable to control heat and cold. Therefore, the only option you have to live is to regain your parents. That is why they are fully raised until the parents heed it.