Beluga whales are found in the Arctic Ocean and its adjoining seas. Also called white whales (for obvious reasons), belugas can blend into icy environments thanks to their trademark color. Unlike most whales, belugas don't have dorsal fins. Experts think this adaptation helps them to preserve body heat by reducing the animals' surface area; it also allows them to swim deftly under extensive ice sheets.
Belugas swim in freezing waters, so it's no coincidence they have the greatest percentage of blubber of any whale. They also have an echolocation organ, called the melon, at the front of their head. Along with hunting and navigating, it helps them find breathing holes in the ice.