Penguins

The signature Species of the Southern Hemisphere (Antarctica) - the mascot if you will - is the penguin. There are not one and no fewer than seventeen species of penguins. Penguins are flightless birds in which several factors are contributing to the reduction of the penguin population. These contributing factors are both man-made and naturally occurring.
?The origin of the word ?penguin? has been the subject of debate for a long period of time. Researchers and historians' theories range from reference to the amount of fat (penguigo in Spanish and pinguis in Latin) penguins possess to the claim that the word was derived from two Welsh words meaning ?white head'.? (Sparks and Soper, 1987) Penguins are comical and funny birds. Blue/black on the upper half of their body and white on the lower half, they look as though they are all dressed up for a formal dinner or show but have no place to go! Penguins are flightless birds, which have adapted to living in the cooler waters of the Southern Hemisphere. They generally live on islands and remote continental regions that are free of land predators. Their inability to fly has been detrimental to their survival on land. Some species of penguins spend as much as 75% of their lives in the ocean, yet they all breed on land or sea ice attached to land. The seventeen species found today are thought to have evolved from flying birds more than forty million years ago. To date, the discovery of all penguin fossil fragments has been limited to the Southern Hemisphere. ?Records show that prehistoric penguins were found within the range of present-day penguins.? (Sparks and Soper, 1987)
All penguins have a very similar torpedo-shaped body form, which is conducive for swimming. They have a large head and a short neck with an elongated body. Penguin species vary greatly in size. For example, the Emperor penguin is the largest of the penguin species, standing 3.7 feet and weighing between sixty and ninety pounds. The smallest penguin in the species is the Fairy penguin, standing only sixteen inches and weighs less than 3 pounds. Penguin's wings are highly modified to form a stiff paddle-like flipper used for swimming. ?Each flipper is covered with short, scale like feathers. The long wing feathers typical of most birds would be too flexible for swimming through water.? (Sparks and Soper, 1987) A penguin's tail is short and wedged shaped with fourteen to eighteen stiff tail feathers. The legs and webbed feet with visible claws on a penguin are set back on the body so that when on land, the penguin is able to stand. ?Penguins walk with short steps or hops, sometimes using their bills or tails to assist themselves on steep climbs.? (del Hoyo, et al., 1992) When in the ocean swimming, penguins use their feet and short stubby tail as a rudder to guide them through the water. Penguin's bones are solid and heavy which help them to remain submerged to reduce the energy that they need for diving.
Penguins are able to withstand the extreme cold because of the insulation provided by their feathers. Feathers are highly specialized, broad and closely spaced helping to keep water away from the penguin's body. Penguins have more feathers than most birds, having about seventy feathers per square inch on their body. Most penguin species goes through one complete molting cycle per year, which usually happens after breeding season. ?The exception to this is the Galapagos penguin which annually go through 2 molts.? (del Hoyo, et al., 1992) For penguins, molting is a very important process because feathers wear out when penguins come in contact with each other, as well as with the ground and water. The molting period varies between one species to another. Usually the time period is anywhere from thirteen to thirty-four days.
Regular preening of the feathers is essential as penguins obtain oil from their tails to coat their feathers for waterproofing. Penguins in warmer temperate zones have a thinner plumage of feathers and fat layer than their counterparts of the polar species. To keep warm in near freezing waters, penguins have a highly developed heat exchanged system of blood vessels in the flippers and legs which helps the heat loss at the core of the body.