Are penguins birds or mammals?

Penguins are a family of flightless, aquatic birds. Distinguished by their typical black and white color scheme, a type of camouflage called "countershading," penguins spend as much as three-fourths of their lives in the ocean hunting for fish, krill and squid.

They are found almost exclusively in the Southern Hemisphere. The penguins that are found on the Galapagos Islands, located approximately 600 miles west of Ecuador in South America, are the only species that are found in the Northern Hemisphere. Penguins are found on the southern coasts of South America, Africa and Australia, and on the ice shelves of Antarctica.