Adaptation of penguins

Adaptation of Penguins in Cold Areas.
One of the most difficult challenges for penguins is maintaining their body temperature under the vastly different conditions on land, where they live andbreed, and in the icy Antarctic water, where they feed. Like other birds, penguins are homoeothermic, maintaining a relatively stable body temperature between 35º and 41º C. However, unlike most otherbirds, penguins do this in a climate where sea temperatures approach -2°C and air temperatures can range from 0°C to a bone chilling -60°C. While metabolism and muscle activity generate body heatinternally, penguins have unique external adaptations to help them conserve this heat. To avoid heat loss, they are insulated by a thick layer of fat, or blubber, under the skin. This helps retain heat, justas in whales, seals and other large cold-water animals. In addition, penguin bodies are covered by a layer of feathers that are more densely packed than in any other birds. The base of their feathersare also downy, to trap air for better insulation. In addition, penguins have evolved behaviours to keep their feathers in good condition and insulate them from the cold wind and water. Theywaterproof themselves by preening, which involves spreading special oily secretions from the uropygial gland at the base of their tail to other areas of their body.

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Penguins have other adaptationsthat help them control temperature. An elaborate circulatory system allows them to retain and dissipate heat easily. The arteries and veins in their extremities are situated very close together sothat they can exchange heat. This is called a “countercurrent” heat exchange system to reflect the to-and-from flow of blood relative to the heart. The layout raises the temperature of blood flowing fromthe flippers and legs to the body core by drawing it past veins carrying already-warm blood to the extremities. Penguins can also increase blood flow to their flippers in order to cool down when...