The penguin breeding strategy in which adults take turns guarding chicks and feeding at sea is called biparental care.
Under biparental care, both parents contribute to raising offspring. One adult may remain with an egg or chick while the other travels to sea to obtain food; the parents then switch roles. This division allows the chick to be protected while still receiving regular meals.
The timing and details differ among species. In emperor penguins, the male incubates the egg while the female travels to sea, and later the parents share chick-rearing duties. In many other penguins, both parents alternate incubation shifts from the beginning.
Biparental care is different from cooperative breeding, in which additional non-parent adults help raise young. Penguins often nest in dense colonies, but colonial nesting alone does not mean that unrelated adults share parental duties.