All 17 species of penguins are found exclusively in the Southern Hemisphere. Emperor Penguins are the tallest species, standing nearly 4 feet tall. The smallest is the Little Blue Penguin, which is only about 16 inches. The fastest species is the Gentoo Penguin, which can reach swimming speeds up to 22 mph. A penguin’s striking colouring is a matter of camouflage; from above, its black back blends into the murky depths of the ocean. From below, its white belly is hidden against the bright surface. Penguins ingest a lot of seawater while hunting for fish, but a special gland behind their eyes—the supraorbital gland—filters out the saltwater from their bloodstream. Penguins excrete it through their beaks, or by sneezing.