The Australia fur seal is an amazing swimmer and diver, diving in excess of 150 m in search of its food. Its diet consists of squid, octopus, rock lobsters and fish. The seals eat their prey whole and later regurgitate the bones.
Being the largest of the fur seals they can eventually reach a weight of 360 kg for the males and 110 kg for the females, with the pups being 5 - 12 kg (for males) and 4 - 10 kg (for females) at birth. They can grow up to a length of 225 cm for the males and the females reaching 170 cm. At birth the pups are black but after they first month they turn a greyish fawn colour with a pale throat before changing to either the male colour, of dark greyish brown with a paler ventral and coarse mane, or the female colour, of a pale fawn to greyish brown with a pale throat and a brown ventral.
Mating occurs over a period of 6 weeks from November to December, with the bulls seeking out territory in October for the largest and most aggressive bulls. The gestation is for 51 weeks which includes a delay of implantation of 3 months. The female gives birth to one pup and she remains on shore for 6 days before returning to the water to mate again and search of food. These pups suckle for 11 months.
The life span for males is 19 years with females living up to 21 years, although there is a pup mortality rate of 15% in the first two months. A small number of seals are killed by sharks (particularly white pointers) and killer whales are also known to eat seals but these are rarely seen near the Australian fur seal colonies. Their main threats to the population are entanglement with lines and nets and also swallowing plastic bags as the seals think they are squid which is popular to their diet. Toxic pollution and oil spills also have a devastating effect on the colonies. The population is estimated at around 25,000 seals.
They are highly fond of company and extremely inquisitive. I realised this when diving at Montague Island, as soon as the boat approaches the island the seals all make a mad rush to the water, they just love playing and coming to investigate those strange new marine creatures with large tanks on their back.
The Australian fur seal is commonly seen in south eastern Australian waters, from Seal Rocks in New South Wales down to Tasmania. They differ from the New Zealand fur seal (which is also found in Australian waters) in that its breeding habitat is on exposed rocky shores (the New Zealand fur seal prefers sheltered boulder beaches), although both the Australian fur seal and the New Zealand fur seal can be found in colonies at Montague Island.