Which gland helps penguins remove excess salt from seawater?

The supraorbital gland helps penguins remove excess salt from seawater.

Penguins often swallow seawater while feeding, and their marine diet also supplies more salt than their bodies need. The supraorbital glands, located above the eyes, filter salts from the bloodstream and release a concentrated salt solution through ducts near the bill.

This adaptation is especially important because penguins spend much of their lives at sea and cannot rely only on fresh water. They can also obtain water from food and, in some circumstances, from melted snow or ice.

The gland is sometimes called the nasal salt gland because its secretions leave through the nasal passages. It is not the preen gland, which produces oil used in feather maintenance. Similar salt-excreting glands occur in other marine birds, including albatrosses and gulls.