whales

Whales are large, fully aquatic marine mammals belonging to the order *Cetacea*. They are characterized by streamlined bodies, flippers, tail flukes for propulsion, and blowholes on top of their heads for breathing air. Whales are divided into two main groups: baleen whales (*Mysticeti*), which filter-feed using baleen plates, and toothed whales (*Odontoceti*), which have teeth and include species such as sperm whales and dolphins.