|All 18 species of penguins live in the Southern Hemisphere from the Antarctic to the equator. Penguins are confined to the Southern Hemisphere because the tropical warm water belt at the equator offers little food to sustain them.|
|Antarctica, on the South Pole, is surrounded by frigid seas. The cold seas of the Antarctic Circumpolar Current are narrowed by the southernmost points of the continents of South Africa and South America. This narrowing causes the water to be diverted north along the western coasts of these continents and creates an upwelling of the deep water within the currents, bringing with it nutrients that encourage growth of plankton. Plankton is eaten by the schooling fish, squid and crustaceans that are, in turn, eaten by penguins.|
Form and Function
|Penguins are flightless, highly specialized marine birds. Although they cannot fly in air their torpedo shape and rigid, paddle like wings give the impression of underwater flight. Penguin swimming speeds range between 1-9 mph, dependent on the species. Some species spend ¾ of their lives at sea. On average, penguins live to be 20 years old.Their bones are solid to decrease buoyancy in the water. Their legs and webbed feet work as rudders and are located far back on the body for streamlining, giving them an upright stance and a waddle when they walk.
Penguins have more feathers than all other birds, up to 80 per square inch. Their feathers are small and lance shaped, with wispy down at the base for warmth. These feathers fit together like the shingles on a roof to keep the cold water out and to pad the penguin against attacks and rough seas. A gland at the base of the tail provides oil that the penguin spreads on its feathers to keep them in good condition and water repellent. Penguins lose and replace all feathers once per year during their annual molt. In the ocean, black and white “tuxedos” provide a terrific camouflage called counter shading. From above, the black back fades into the dark ocean depths, while the white belly hides the penguin from below by blending it into the bright ocean surface.
When it comes to telling penguin species apart, all of the major differences are found on the head. On the ocean, only the head is visible as penguins tend to float low in the water.
The beak is sharp edged and hooked to trap wriggling fish. The tongue and mouth are lined with backward pointing spines that assist in holding on to slippery fish. While capturing their prey penguins undoubtedly swallow salt water. Salt glands located internally, over each eye, remove the salt from their bodies.