“Whale” is the common name for a variety of marine mammals. The Latin word cetus gives the species its scientific title, Cetacea. Whales come in two categories of Cetacea. The largest, Mysticeti, are characterized by their baleen, sieve-like structures in their upper jaw that are used to filter food from the seawater. The other category, Odontoceti, have teeth, such as sperm whales and orcas.