They live almost exclusively in the Southern Hemisphere, with only one species, the Galapagos penguin, found north of the equator.
On average, adults are about 1.1 m (3 ft 7 in) tall and weigh 35 kg (77 lb)
Penguins have black backs and wings with white fronts. A predator looking up from below has difficulty distinguishing between a white penguin belly and the reflective water surface. The dark plumage on their backs camouflages them from above
Penguins have a thick layer of insulating feathers that keep them warm in the water
Adult penguins molt all of their feathers once a year following the breeding period
The largest living species is the emperor penguin
Diving penguins reach 6 to 12 km/h (3.7 to 7.5 mph), though there are reports of velocities of 27 km/h (17 mph)
Most penguins feed on krill, fish, squid and other forms of sea life
They can drink salt water because their supraorbital gland filters excess salt from the bloodstream.
Only a few species of penguin actually live in Antarctica, they are not found only in cold climates
On land, penguins either waddle on their feet or slide on their bellies across the snow while using their feet to propel and steer themselves
Upon arrival at the colony, each bird returns to the nest that it left the previous year and generally rejoins its mate of the previous year unless the death of the latter forces it to choose another partner.