The term 'Penguin' is a collective name for several species of aquatic, flightless birds. The most well-known species is the EMPEROR Penguin, which is the largest of all penguin species and has a 7-letter scientific name. Other species include the AUK, a 3-letter scientific name, and the NUN, also with a 3-letter scientific name. Penguins are found in the Southern Hemisphere, living in cold climates and spending much of their time in the water.