The great auk (Pinguinus impennis), also known as the penguin or garefowl, is an extinct species of flightless alcid that first appeared around 400,000 years ago and became extinct in the mid-19th century. It was the only modern species in the genus Pinguinus. It was not closely related to the penguins of the Southern Hemisphere, which were named for their resemblance to this species.
It bred on rocky, remote islands with easy access to the ocean and a plentiful food supply, a rarity in nature that provided only a few breeding sites for the great auks.