Whale than males. Baleen whales have no teeth; instead they have plates of baleen, a fringe-like structure used to expel water while retaining the krill and plankton which they feed on. They use their throat pleats to expand the mouth to take in huge gulps of water. Balaenids have heads that can make up 40% of their body mass to take in water. Toothed whales, on the other hand, have conical teeth adapted to catching fish or squid. Baleen whales have a well developed sense of "smell", whereas toothed whales have well-developed hearing − their hearing, that is adapted for both
Baleen baleen. These baleen bristles are arranged in plates across the upper jaw of the whale. As a material for various human uses, baleen is usually called whalebone. It is not to be confused (but often is) with whale bone or whale's bone meaning the actual bones of whales, used in carving, for cutlery handles and other uses for the bones of various large species. Like other bone materials, this often functioned as a substitute for ivory. Depending on the species, a baleen plate can be long, and weigh up to . Its hairy fringes are called baleen hair or whalebone-hair.