Sphenisciformes
Sphenisciformes is an order of flightless, aquatic birds that comprises the penguins. They are found almost exclusively in the Southern Hemisphere, with only one species, the Galapagos penguin, found north of the equator. Penguins are highly adapted for swimming and diving, with wings evolved into flippers, dense bones, and streamlined bodies. They are social animals that live in colonies, often numbering in the hundreds or thousands.
Common Names
The term "penguin" is derived from the Welsh word "pen gwyn," which means "white head." This refers to the white patches on the head of some penguin species. Other common names for penguins include "sea birds," "diving birds," and "flippered birds."
Characteristics
Penguins exhibit several unique adaptations that allow them to thrive in aquatic environments:
- Flippers: Their wings have evolved into flippers, which are powerful and efficient for swimming and diving.
- Dense bones: Penguins have dense bones that help them stay submerged in water.
- Streamlined body shape: Their torpedo-shaped bodies minimize water resistance, allowing for efficient swimming.
- Thick feathers: Their feathers are tightly packed and waterproof, providing insulation against cold water.
- Counter-current heat exchange: Their circulatory system features a counter-current heat exchange system that minimizes heat loss in cold waters.
- Social behavior: Penguins are highly social animals and live in colonies for breeding, foraging, and protection.
Environments
Penguins are found in a variety of marine environments in the Southern Hemisphere, including:
- Antarctica: The continent of Antarctica is home to the largest populations of penguins, including the emperor penguin, Adélie penguin, and chinstrap penguin.
- Subantarctic islands: Islands south of the Antarctic Circle, such as the South Shetland Islands and the South Orkney Islands, are also inhabited by penguins.
- Coastal regions of South America, Africa, and Australia: Penguins are found along the coasts of these continents, where they forage for food in colder waters.
- Galapagos Islands: The Galapagos penguin is the only species of penguin found north of the equator. It lives in the cool waters of the Galapagos Islands.
References
Wikipedia: Sphenisciformes
World Wildlife Fund: Penguins
National Geographic: Penguins