The supraorbital gland is a type of lateral nasal gland found in some species of marine birds, particularly penguins, which removes sodium chloride from the bloodstream. The gland's function is similar to that of the kidneys, though it is much more efficient at removing salt, allowing penguins to survive without access to fresh water. Contrary to popular belief, the gland does not directly convert saltwater to freshwater. The term supraorbital refers to the area just above the eye socket (which is known as the orbit).