A fossil penguin named Kumimanu biceae stood about 1.65 meters tall. It weighed about 100 kilograms. The Kumimanu fossil is about 55 to 60 million years old, close in age to the oldest known penguins. The name Kumimanu, given to a giant fossil penguin, means "monster bird" in Maori. Early penguins lived in warm seas, so penguins did not begin in the cold. Penguins are birds that cannot fly. Most penguins live south of the equator, in the Southern Hemisphere. The Galapagos penguin lives on islands on the equator. It is the only wild penguin found north of the equator.

Penguins have short, overlapping feathers. They form a waterproof coat. Emperor penguins stay warm with several layers of scale-like feathers and a layer of fat. Penguins huddle close together to stay warm. Penguins have black on their backs and white on their bellies. The black and white coloring is called countershading and makes a penguin hard to see in the water. Penguins swim by pushing themselves along with their flippers. Penguin parents take turns keeping the eggs warm. A father emperor penguin keeps the egg warm on top of his feet, under a flap of skin.

Emperor penguins breed in the middle of the Antarctic winter. Emperor penguins breed on sea ice and also hunt along its edge, so they depend on it. Most emperor colonies sit on fast ice, sea ice that is frozen to the land or to grounded icebergs. Emperor penguins rely on stable fast ice for about eight months of the year, from breeding until chicks leave. Emperor penguins build up fat before winter and live on it while they fast during breeding. Only two kinds of penguin, the emperor and the Adelie, are true residents of the Antarctic continent.

As of April 2026, satellite images show about a 10 percent loss of emperor penguins across Antarctica between 2009 and 2018. As of November 2026, climate change is the main cause of the fall in emperor penguin numbers. As of November 2026, about two-thirds of the 18 penguin species are listed as threatened by the IUCN. As of November 2026, the Galapagos penguin is endangered. As of November 2026, only a few thousand Galapagos penguins are left; counts differ, from 1,200 to about 2,000-3,000. As of November 2026, African penguins are critically endangered, and their numbers have been falling since the early 1900s. Penguins are indicators of the health of the ocean and of climate change.

Words to know

• fossil: old remains
• equator: Earth's middle line
• huddle: tight group
• threatened: in danger
• indicators: signs