Science, Tech, Math › Animals & Nature Differences Between Baleen and Toothed Whales Characteristics of the Two Major Whale Groups Share Flipboard Email Print Adult humpback whale. Alastair Pollock Photography/Moment Open/Getty Images Animals & Nature Marine Life Marine Life Profiles Marine Habitat Profiles Sharks Key Terms Amphibians Birds Habitat Profiles Mammals Reptiles Wildlife Conservation Insects Forestry Dinosaurs Evolution View More By Jennifer Kennedy Marine Science Expert M.S., Resource Administration and Management, University of New Hampshire B.S., Natural Resources, Cornell University Jennifer Kennedy, M.S., is an environmental educator specializing in marine life. She serves as the executive director of the Blue Ocean Society for Marine Conservation. our editorial process Jennifer Kennedy Updated April 11, 2018 Cetaceans are a group of aquatic mammals which include all the varieties of whales and dolphins. There are over 80 recognized species of cetaceans, including both freshwater and saltwater natives. These species are divided into two main groups: the baleen whales and the toothed whales. While they are all considered whales, there are some important differences between the two types. Baleen Whales Baleen is a substance made of keratin (the protein that makes up human fingernails). Baleen whales have as many as 600 plates of baleen in their upper jaws. Whales strain seawater through the baleen, and hairs on the baleen capture fish, shrimp, and plankton. The salt water then flows back out of the whale's mouth. The largest baleen whales strain and eat as much as a ton of fish and plankton each day. There are 12 species of baleen whales which live all over the world. Baleen whales were (and still sometimes are) hunted for their oil and ambergris; in addition, many are injured by boats, nets, pollution, and climate change. As a result, some species of baleen whales are endangered or near extinction. Baleen whales: Are generally larger than toothed whales. The largest animal in the world, the blue whale, is a baleen whale.Feed on smaller fish and plankton with a filtering system made up of hundreds of baleen plates.Tend to be solitary, although they occasionally gather in groups to feed or to travel.Have two blowholes on top of their head, one right next to the other (toothed whales have only one).Female baleen whales are larger than males of the same species. Examples of baleen whales include the blue whale, right whale, fin whale, and humpback whale. Toothed Whales It may come as a surprise to learn that the toothed whales include all species of dolphins and porpoises. In fact, 32 species of dolphins and 6 species of porpoises are toothed whales. Orcas, sometimes called killer whales, are actually the world's largest dolphins. While whales are larger than dolphins, dolphins are large (and more talkative) than porpoises. Some toothed whales are freshwater animals; these include six species of river dolphins. River dolphins are freshwater mammals with long snouts and small eyes, which live in rivers in Asia and South America. Like baleen whales, many species of toothed whales are endangered. Toothed whales: Are generally smaller than baleen whales, although there are some exceptions (e.g., the sperm whale and Baird's beaked whale). Are active predators and have teeth that they use to catch their prey and swallow it whole. The prey varies depending on species but can include fish, seals, sea lions or even other whales.Have a much stronger social structure than baleen whales, often gathering in pods with a stable social structure.Have one blowhole on top of their head.Unlike baleen whales, males of toothed whales species are usually larger than females. Examples of toothed whales include the beluga whale, bottlenose dolphin, and common dolphin.