A penguin’s eyes are adapted for underwater vision. On land, penguins are nearsighted Penguins are sensitive to violet, blue, and green light. If a penguin is too warm, it holds its flippers away from its body, so that both surfaces of the flippers are exposed to air, thus releasing heat. The internal temperature range of penguins is 100-102 degrees. Emperor Penguins huddle together to conserve heat. As many as 6,000 males will cluster together while incubating eggs during an Antarctic winter. An average penguin lives for 15-20 years.
The emperor penguin is the largest of penguins standing at 3.7ft and weighing between 60-90lbs. The smallest penguin is the fairy penguin standing at 16in and weighing only 2.2lbs. Each penguin species has distinctive markings and coloration. All adult penguins are countershaded. They are dark in their backs and white on their front. The dark dorsal side blends in with the dark ocean, when viewed from above and their white ventral side blends in with the lighter surface of the ocean, when viewed from below. This prevents predators or prey from being able to distinguish the penguin from its environment.
Penguins generally live on islands and remote continental regions that are free from land predators and where their inability to fly is not a needed survival skill. They are also usually found near nutrient-rich, cold water currents that provide an adequate food supply. Penguins are found on every continent in the Southern Hemisphere and are abundant on many temperate and subantarctic islands. Penguins can live in a variety of climates ranging from the Galapagos penguins on tropical islands to emperor penguins restricted to Antarctica. Each habit comes with its own predators, which include killer whales, leopard seals and giant petrels. Each penguin species has slightly different food preferences, but a penguin’s diet usually consists of krill, fish and squid.
Penguin calls are unique to each penguin, allowing partners to recognize each other and their chick. This is important because in a large group, you can hardly tell penguins apart by sight. Penguins communicate by vocalizing and performing physical behaviors called displays. Displays are used for mating purposes, to defend against intruders, to identify nesting territories and to identify individual members.
Most penguins are monogamous. With the exception of the emperor penguin, penguin partners take turns incubating the eggs, allowing each mate to leave and feed at sea. The incubation period varies with species and ranges from 30 days- 66 days. Once hatched, chicks require attentive parents for survival. Both parents feed their chick regurgitated food. Adult penguins recognize and feed only their own chicks and are able to identify their young by their chick’s distinctive call. It is vital that the parents protect their chick from predators. Many predators will prey on chicks that have wandered away from their parents or are too young to defend themselves.