Whales With a last flick of its fluke, a sperm whale disappears beneath the waters of New Zealand. Since each fluke (tail fin) is unique, like a human fingerprint, scientists use flukes to monitor the habits and migrations of individual whales. A beluga whale swims in the cold waters of Nova Scotia, Canada. Although belugas are also known as white whales, beluga calves are born gray or brown. It takes about five years before a young beluga turns pure white. A family of orca whales swims to the surface in Aialik Bay, Alaska. Orca whales, also called killer whales, usually hunt in large family groups called pods. Each pod uses distinct noises to communicate underwater, keeping its family members from getting mixed up with the wrong group of orcas! A humpback whale flies through the air near the coast of Alaska. This behavior, called breaching, starts with the whale's powerful tail fin, or fluke, propelling the humpback out of the water. Then these massive whales sail through the air and hit the water with a giant splash. A pygmy whale glides through the clear blue waters of the Hawaiian Islands. Although related to orcas (killer whales), pygmy killer whales are only a third the size just six and half feet (two meters) long. These whales are also all black, except for the tiny bit of white found along their mouths. An endangered sperm whale, swimming in Japanese waters, opens its mouth near the surface. Their heads are enormous for good reason sperm whales have the largest brain of any animal known to have lived on Earth. A gray whale emerges from the water in Mexico's San Ignacio Lagoon, showing off its baleen. Baleen is a substance that grows in plates in the mouths of baleen whales. Each individual piece of baleen is about 18 inches (46 centimeters) long! Baleen helps the gray whale, and other baleen whales, strain tasty morsels of food from the seawater.