Mammalogy Lab- Cetaceans: Suborder Odontoceti

Cetaceans are split into two main Suborders: S.Mysticeti and S.Odontoceti. Suborder Odontoceti contains all the toothed whales, and there are features common to all families in the suborder. These include the presence of teeth, an asymmetrical skull (likely used in echolocation), a single external nares, and a melon. The melon is an oil-filled structure most evident in sperm whales that is thought to be used to focus sound during echolocation. Odontocetes also have an ear bone (petrosal) that is surrounded by sinuses and entirely disconnected from the skull, which serves to reduce the vibrations passing into the bones of the skull. In Mammalogy lab we looked at four of the families of Odontocetes: F. Delphinidae (dolphins), F. Phocoenidae (porpoises), F. Monodontidae (belugas and narwhals), and F. Physeteridae (sperm whales and pygmy sperm whales). F. Delphinidae have a beak-like snout, conical teeth, a skull that is concave from the tip of the premaxillary bone to the nasals, and flippers that are shaped like sickles. F. Phocoenidae on the other hand have spade-like teeth, a blunt rostrum, and flippers that are paddle-shaped. F. Monodontidae have skulls that in profile look flat or convex, forward-pointing conical teeth, and do not have a dorsal fin. F. Physeteridae have the most asymmetrical skull of all the Odontocetes and do not have teeth in their upper jaw.