The HCG hormone is the answer possibly
What do you need examples of?
Answer:
the penguins have a special care process since the hatching of the egg, the newborns receive care from their parents and have warmth from them placing themselves between their paws, the parents take turns caring for them and when the father is not with the chick, he goes in search of food, which he gives regurgitated, then the cris can go to a kindergarten where others of the same age are cared for by a herd of penguins, however his parents go to the sea and feed and continue to bring food to their son, this process it is kept until they change plumage and are ready to get their food on their own.
