Endangered penguins get rid of their firstborn for the survival of the species.

Scientists have figured out why endangered two-egg-laying crested penguins drop the first and only hatch the second, which emerges about five days later. It turned out to be a strategy for the survival of the species. The first egg is formed in the body of the female when she is still heading to the nesting sites by sea, so it is small. The second is already on dry land. It is larger, which means that the chick hatched from it is more likely to survive.