The great penguins are the two giants of the family: the king penguin pictured, 35-37 inches (90 cm) tall and 20-35 lbs (9-16 kg), and the emperor penguin, the largest penguin alive at about 45 inches (115 cm) and up to 88 lbs (40 kg). Both have silver-grey backs, white fronts and glowing orange patches on the sides of the head.
They are the deepest divers of all birds. An emperor penguin can reach 1,800 feet (550 m) and stay under for more than 20 minutes, slowing its heart to a few beats a minute. A thick layer of fat and a coat of densely packed feathers keep them warm in the coldest place on Earth.
Great penguins build no nest. The single egg is carried on the parents' feet, tucked under a fold of belly skin called the brood pouch.
Emperor penguins live only in Antarctica and breed on the frozen sea ice in the dead of winter, the only animal that does so. King penguins live further north on sub-Antarctic islands such as South Georgia, the Crozet Islands and Macquarie Island, where they breed on beaches and gently sloping valleys.
Both feed in the cold, food-rich waters of the Southern Ocean.
King and emperor penguins eat fish, especially lanternfish, along with squid and krill. They hunt on deep dives in open water and under the ice, and may travel hundreds of miles from the colony to find food for their chicks.
Male emperor penguins incubate the egg through the Antarctic winter, standing for about four months without eating in temperatures of -40 and winds over 100 mph (160 km/h). They survive by huddling in tight groups and taking turns on the outside.
King penguins take 14-16 months to raise a chick, so a pair can breed only twice in three years. Their brown, woolly chicks, once mistaken for a separate species, stand in enormous creches through the winter while the parents fish.
Aptenodytes contains just two living species, the emperor and king penguins. The IUCN lists the king penguin as Least Concern; its numbers have grown since the end of sealing and whaling. The emperor penguin is listed as Near Threatened and was declared a threatened species by the United States in 2022.
The emperor's future depends on sea ice. Several colonies have failed completely in recent years when the ice broke up before chicks had grown their waterproof feathers.
