Flatheaded Bottlenose Whale

This species resembles the northern bottlenose whale, with a bulbous melon (especially in adult males), tubelike beak, throat grooves, small dorsal fin, small blunt flippers, and flukes with no notch (or only a shallow one). These animals are light brown to dull yellow. The belly and probably much of the head are lighter. Large animals can be covered with light splotches, scratches, and scars. The colour pattern of young calves is unknown. There is a single pair of conical teeth at the tip of the lower jaw, which erupts only in adult males, and is not visible outside the closed mouth. There may be a smaller second pair, and several sets of vestigial teeth, as well. Can be confused with: Arnoux's beaked whales can be distinguished from southern bottlenose whales by differences in dorsal fin and head shape, and from Cuvier's beaked whales and Mesoplodon primarily by head shape and body patterning.

Maximum known sizes are 7.8 m for females and about 7.2 m for males. If females are, in fact, larger than males, this species differs from its northern counterpart. However, the disparity is more likely a result of the small sample size of measured animals. Length at birth appears to be around 2 m.

Pods of less than 10 are most common, but groups of up to 25 have been seen. They are deep divers that can remain below for over an hour. There is essentially nothing known of the reproductive biology of this species. Southern bottlenose whales are thought to take primarily squid, but probably also eat fish and possibly squid.

Although never taken commercially, some southern bottlenose whales have been killed during whaling for research purposes. Recently, several of this species have been recorded as accidental victims of driftnet fishing in the Tasman Sea. Numbers taken annually are not known, however. IUCN: Insufficiently known.