The island is no stranger to marine mammals. Aside from birds, marine mammals are the most common wildlife on Montague. This is due to the East Australian Current, which runs near the island. The current attracts baitfish, predator fish and squid, which in turn attract larger marine mammals.
Fur seals are one of the more common marine mammals on Montague Island. While the highest number of fur seals are seen during winter and spring, some fur seals are annual residents of the island. During peak season, more than 1000 fur seals can be seen on and around the island, but this number decreases to 200 post-December. If visitors are lucky, they might even be able to sopot some baby seal pups after December!
Annual island fur seals are typically one of two species: the Australian fur seal and the New Zealand fur seal. While Australian sea lions, antarctic fur seals and carnivorous leopard seals have also been seen on the island, they are not common. Australian fur seals, scientifically known as Arctocephalus pusillus doriferus, prefer to sit on rocks in large groups. These seals sit so close to each other that they are oftentimes directly on top of one another. New Zealand fur seals, on the other hand, will be near Australian fur seals but enjoy their personal space. In fact, they have been known to attack other seals that get too close.