HUMBOLDT PENGUINS IN DUBLIN ZOO
Image by infomatique
The number of penguin species has been and still is a matter of debate. The numbers of penguin species listed in the literature varies between 16 and 19 species. Some sources consider the White-Flippered Penguin a separate Eudyptula species, although today it is generally considered a subspecies of the Little Penguin (e.g. Williams, 1995; Davis & Renner, 2003). Similarly, it is still unclear whether the Royal Penguin is merely a color morph of the Macaroni penguin. Also possibly eligible to be treated as a separate species is the Northern population of Rockhopper penguins (Davis & Renner, 2003). Although all penguin species are native to the southern hemisphere, they are not, contrary to popular belief, found only in cold climates, such as Antarctica. In fact, only a few species of penguin actually live so far south. Three species live in the tropics; one lives as far north as the Galápagos Islands (the Galápagos Penguin).
The largest living species is the Emperor Penguin (Aptenodytes forsteri): adults average about 1.1 m (3 ft 7 in) tall and weigh 35 kg (75 lb) or more. The smallest penguin species is the Little Blue Penguin (also known as the Fairy Penguin), which stands around 40 cm tall (16 in) and weighs 1 kg (2.2 lb). Generally larger penguins retain heat better, and thus inhabit colder regions, while smaller penguins are found in temperate or even tropical climates (see also Bergmann’s Rule). Some prehistoric species attained enormous sizes, becoming as high as an adult human; see below for more.
Most penguins feed on krill, fish, squid, and other forms of sealife caught while swimming underwater. They spend half of their life on land and half in the oceans.
When mothers lose a chick, they sometimes attempt to steal another mother’s chick, usually unsuccessfully as other females in the vicinity assist the defending mother in keeping her chick.
Penguins seem to have no fear of humans, and have approached groups of explorers without hesitation.