BEAKED WHALE

any of a family (Ziphiidae, or, in some classifications, Hyperoodontidae) of medium-sized toothed whales (suborder Odontoceti), encompassing 6 genera and about 18 species, including the bottlenose whales. Members of the family are characterized by an extended beaklike snout, small rounded flippers, a dorsal fin set toward the rear, two throat grooves that meet under the chin, and the lack of a central notch in the wide flukes. The stomach is compartmented, containing up to 14 sections. In almost all beaked whale species, functional teeth are limited to one or two pairs, present only in the lower jaw and usually erupting through the gums only in the male whale. In the remarkable strap-toothed whale (Mesoplodon layardi), these teeth curve up and out, around the upper jaw, holding it partially shut. Shepherd's beaked whale (Tasmacetus) is also unusual, as it has numerous small functional teeth. Beaked whales are distributed throughout the world, although certain species are limited to one ocean. Ranging in size from 3.5 metres (12 feet) for Hector's beaked whale, M. hectori, to 12.8 m for the giant bottlenose whale, Berardius bairdii, these whales weigh between 1,000 and 11,000 kilograms (1.1 and 12 tons). Colour is variable but is usually some combination of gray or black with white. Their bodies are often covered with long scars from fighting with each other. Beaked whales are the least known of the large mammals, and the mystery continues as the bodies of undescribed species occasionally drift ashore. Rapid swimmers and deep divers, beaked whales are teuthophagous (squid-eating), although most also eat fish and bottom-dwelling invertebrates. Some are solitary or travel in small groups, while others may appear in pods of 30 or more. Groups often surface and dive in unison. See also bottlenose whale.