Baleen whale

Mysticeti (/ˈmɪstʌsɛtiː/) (from Greek ὁ μῦς τὸ κῆτος "the mouse, the whale so called" ), or baleen whales, are a widely distributed and diverse parvorder of carnivorous marine mammals. They comprise the families Balaenidae (right whales), Balaenopteridae (rorqual), Eschrichtiidae (the gray whale), and Cetotheriidae (the pygmy right whale). There are currently 15 species of baleen whale. While cetaceans were historically thought to have descended from mesonychids, molecular evidence supports them as relatives of even-toed ungulates (Artiodactyla). Baleen whale split from toothed whales (Odontoceti) around 34 million years ago.

Baleen whales range in size from the 20 ft (6 m) and 6,600 lb (3,000 kg) pygmy right whale to the 112 ft (34 m) and 190 t (210 short tons) blue whale, which is also the largest creature. They exhibit sexual dimorphism. Baleen whales can have streamlined or large bodies, depending on the feeding behavior, and two limbs that are modified into flippers. Though not as flexible and agile as seals, baleen whales can swim very fast. Baleen whales use their plates to filter out food from the water by either lunge-feeding or gulp-feeding. Baleen whales have fused neck vertebrae, and are unable to turn their head at all. Baleen whales have two blowholes. Some species are well adapted for diving to great depths. They have a layer of fat, or blubber, under the skin to keep warm in the cold water.