Dolphins Whales and Porpoises: Cetacea

Cetaceans are found in all oceans of the world. In the Arctic and Antarctic they avoid ice-covered water, since they must rise to the surface to breathe. Dolphins live in the ocean, but are also found in several freshwater rivers in Asia and South America.

The ocean is divided into different zones or regions based on depth, closeness to land, and underwater features. Cetaceans inhabit virtually all ocean zones, including zones in semi-enclosed water such as the Red and Black Seas. Cetaceans that live in freshwater rivers inhabit clear, rapidly flowing water and dark muddy water.

Members of this order are primarily carnivores, meat eaters. Baleen whales have evolved special filter-like structures to gather small shrimp, small fish, squid, and plankton. Other cetaceans actively hunt prey, either alone or in cooperative groups. Typically they eat whatever fish are found in the oceanic zone that they inhabit. Many also eat squid, octopus, shrimp, and crabs. A few species, especially the killer whale, hunt other whales, seals, sea lions, sea turtles, and sea birds.