ARNOUX'S BEAKED WHALE Berardius arnuxii
The second largest beaked whale, Arnoux’s is probably the most southernmost ranging of the family. The northern limit of its range is at about 34°S and from there it ranges to the edge of the Antarctic pack ice and beyond – it is regularly found in open leads in the pack ice 50km or more from the open sea. Although rarely observed in the open ocean the occurrence of individuals in confined space of ice leads has allowed some opportunistic studies of their behaviour. This appears to be a fairly sociable species (like its northern hemisphere counterpart Baird’s beaked whale) – with no aggression being recorded between individuals even in confined surroundings. A typical dive appears to be about 40 minutes, and may be up to 70 minutes in duration. On average they surface for between 1.2 and 6.8 minutes and breath at a rate of 9.6 breaths per minute – about once every 6 seconds. Of 30 animals closely examined in ice leads 11 were toothless, 16 had one pair of teeth and 3 had two pairs (always in the lower jaw) but how this related to the age and sex of the animals involved isn’t known. Given its range this species appears able to exploit a feeding niche under the pack ice.