Southern bottlenose whale
The southern bottlenose whale is one of the least well-studied species in the family Ziphiidae and forms an anti-tropical species pair with the northern bottlenose whale. Inhabiting the deep, oceanic waters of the southern polar region, this is the most commonly sighted species of beaked whale in the Antarctic.
The Southern bottlenose whale is a large, robust beaked whale. It has a bulbous melon which becomes larger in older males. The forehead is steep, and the stubby beak is well defined resembling the beak of several dolphin species. Two small conical teeth erupt at the tip of the lower jaw in males although these are not always seen outside of the jaw. It has small pointed flippers that fit into 'flipper pockets' when the animal is diving, and a small, pointed, triangular or falcate dorsal fin set well back on the body. The flukes are broad with concave trailing edges and no notch. The body is pale tan or olive brown in colour with extensive scarring, especially on older males. Whitish spots on the belly and flanks are likely to be scars resulting from the bite of cookie cutter sharks. The head, face, and belly are a paler cream colour. In general, females are darker with a smaller melon. Confusion may occur with the other Ziphiidae in its range, especially Arnoux's beaked whale. The distinct beak and bulbous melon, combined with its large size and colouration allow for proper identification.
Very little is known about the behaviour of southern bottlenose whales because their range is so remote. They are usually found in small groups of between 1 and 10 animals, although larger groups of up to 25 individuals have been encountered. They have a bushy blow, 1-2m high, which tilts forward slightly. Known to avoid vessels they have been seen breaching and porpoising away from boats. A deep diving species, southern bottlenose whales feed on squid and some deep-water fish species. Southern bottlenose whales are thought to be migratory in nature and in summer months are found within 200kms of the ice-edge. Like other beaked whales, the southern bottlenose whale is an oceanic species and is rarely found on the continental shelf.
The range of the Southern bottlenose whale extends in a circumpolar band around the southern hemisphere from Antarctica north to 30°S. It has never been hunted on a large scale, however it is occasionally caught in driftnets. As with other beaked whales species, the southern bottlenose whale is probably particularly susceptible to the effects of loud anthropogenic noise. Illegal fishery activities in its range may result in prey depletion and other threats may include climate change. Global abundance has been estimated as in excess of 500,000 individuals and the IUCN has categorised this species as of ‘Least Concern'.