These animals breathe through a blowhole at the top of their head.
The smallest animal in this order is named for the naturalist Philibert Commerson. Many animals within this order possess a mass of adipose tissue in the forehead called a melon. The closest living relatives of this extant order are the hippopotami. The carcasses of many members of this order are known as "falls," and provide a rich ecosystem in the bathyal and (*) abyssal zones. Some animals in this order have cochleae with the highest amount of innervation of any mammal, enabling them to carry out a bat-like form of echolocation; other animals in this order generate sound with the spermaceti organ. These animals breathe through a blowhole at the top of their head. For 10 points, name this order of marine mammals consisting of porpoises, dolphins, and whales.
The smallest animal in this order is named for the naturalist Philibert Commerson.
cetaceans [or Cetacea; prompt on whales before mentioned; prompt on dolphins before mentioned; prompt on porpoises before mentioned]