One Adelie penguin looks doubtfully at the water while another cries out for it to get a move on. No penguin wants to be the first one in, so they egg each other on with a barking call heard nowhere else but on ice. They're not afraid of the cold. The water holds something far worse than a case of the shivers — leopard seals, which patrol the coastline of Antarctica, waiting for an Adélie with poor timing to dive in. Learn more about penguins and Antarctica on Polar Discovery.
(Photo by Chris Linder, Woods Hole Oceanographic Institution)