Penguins are characterized by their distinctive tuxedo-like appearance, with a black back and wings and a white belly.
In terms of size, penguins can range from small to large, depending on the species. The smallest species is the Little penguin (Eudyptula minor), which reaches a height of around 30 cm (12 inches) and a weight of around 1 kg (2.2 lbs). On the other hand, the largest species is the Emperor penguin (Aptenodytes forsteri), which reaches a height of around 122 cm (48 inches) and a weight of up to 45 kg (99 lbs).
They are easily recognized amongst other birds by their long slender bodies and upright posture. They also have stiff wings that stick out from their body due to the inability to hold them against their bodies. All species have some variation of black and white feathers with some species containing yellow and orange colorings as well.
Penguins can be exclusively found in the southern hemisphere (with galapagos penguins being the only exception). Species found in the Antarctic and sub-Antarctic or oceanic. They prefer to breed on coasts and pack ice. The species that live closer to the equator tend to prefer habitats of inshore waters and they will breed in coastal or forest habitats.
Penguins inhabit a variety of coastal habitats, including rocky shores, cliffs, sandy beaches, and ice shelves. They are found in a range of latitudes, from the equator to the poles, and are adapted to living in a range of temperatures, from tropical to subantarctic. They are also adapted to living in cold climates, with a thick layer of insulating feathers and a countercurrent heat exchange system in their blood vessels that helps to keep them warm. Most species of penguins are also adapted to swimming and diving, with streamlined bodies, webbed feet, and powerful flippers that allow them to swim at high speeds underwater.
The diet of penguins consists mainly of small fish, such as anchovies, sardines, and krill, as well as squid and other small marine invertebrates. They are skilled hunters and divers, and are able to forage for food in the cold waters surrounding their breeding colonies.
They are very skilled divers and swimmers. They use their flippers to hunt for prey in the ocean. Movements and land travel vary from species to species while some waddle along the shoreline and others will hop.
Some will toboggan across snow, which is sliding along the snow using their flippers and feet to propel them across the snow. It conserves energy while moving quickly.
Most are monogamous and will stick with the same nesting partner for their entire lifespan only switching if one partner passes. Males and females share the duties of caring for chicks, with varying responsibilities among species when it comes to incubation, brooding, and feeding.
There are 18 species of penguins, which are divided into six genera:
- Aptenodytes: This genus includes the Emperor penguin (Aptenodytes forsteri) and the King penguin (Aptenodytes patagonicus).
- Eudyptes: This genus includes the Crested penguins, such as the Macaroni penguin (Eudyptes chrysolophus), the Royal penguin (Eudyptes schlegeli), and the Rockhopper penguin (Eudyptes chrysocome).
- Pygoscelis: This genus includes the Adélie penguin (Pygoscelis adeliae), the Chinstrap penguin (Pygoscelis antarcticus), and the Gentoo penguin (Pygoscelis papua).
- Spheniscus: This genus includes the Banded penguins, such as the African penguin (Spheniscus demersus), the Magellanic penguin (Spheniscus magellanicus), and the Galapagos penguin (Spheniscus mendiculus).
- Megadyptes: This genus includes the Yellow-eyed penguin (Megadyptes)
- Eudyptula: This genus includes the Little penguin (Eudyptula minor) and the Blue penguin (Eudyptula minor).
In terms of conservation status, some species of penguins are endangered or vulnerable, while others are of least concern. The International Union for Conservation of Nature (IUCN) assesses the conservation status of penguin species as follows:
- Endangered: African penguin, Yellow-eyed penguin, Erect-crested penguin
- Vulnerable: Fiordland penguin, Snares penguin, Magellanic penguin, Galapagos penguin
- Near Threatened: King penguin, Gentoo penguin, Chinstrap penguin
- Least Concern: Emperor penguin, Adélie penguin, Little penguin, Blue penguin, Macaroni penguin, Royal penguin, Rockhopper penguin