Australian sea lion: much more than a weird wet dog

Name: Australian sea lion (Neophoca cinerea)

Size: Length 2-2.5 metres, weight up to approximately 100kg (females) or 250kg (males)

Diet: Carnivores, eating a variety of demersal fish, elasmobranchs (rays), rock lobster, cephalopods (squid, cuttlefish, octopus) and gastropods

Habitat: South coast of Australia including WA and SA

Conservation status: Endangered

Superpower: Australian sea lions are the only seal that does not breed annually, instead getting together every 17.5 months.

Photo of two adult australian sea lions in shallow water on a beach
Australian sea lions on Kangaroo Island, South Australia. Credit: Marc Dozier / The Image Bank / Getty Images.

The Australia sea lion is the only pinniped, or seal, found exclusively in Australia. Many people can recount a tale of encountering a friendly sea lion in the water and of how agile, curious and playful these marine mammals can be.

Australian sea lions may appear like large, docile, goofy dogs when resting on islands between foraging forays, but if approached they can move quickly over land and inflict a nasty bite if they are threatened – living up to their leonine name. They like to feed on prized and highly palatable fish species, including rock lobster and salmon – putting them in direct competition with humans.

Adult male sea lions in good breeding condition are pigeon-chested and can weigh over a couple of hundred kilograms. They sport blonde manes on the crown of their heads that contrasts starkly with their dark coats. Males are particularly protective in the breeding colonies, guarding their mates early in the breeding season.

Photograph of three australian sea lions on the beach a pup adult male with golden back and adult female
An Australian sea lion pup, adult male and adult female. Credit: Holly Raudino.

Female sea lions, also known as ‘cows’, will often return to breed at the island where they were born. If a pup is approached or threatened while its mum is at sea foraging, a cow will defend the pup, even if it is not her own!

The pups are born dark brown, with endearing large, teary, wide eyes. Their fur lightens over a few months, becoming a light silver grey when they are fully moulted. Although weaning usually occurs sooner, there are records of some suckling for 18 months.

If life was only about feeding and breeding, some may think the sea lion, particularly the males, lead an idyllic and charmed life. However, all is not well for Australian sea lions. They reach sexual maturity quickly, with females breeding at 4-6 years of age, but their unusual breeding cycle, strong loyalty to their natal islands, and differences in breeding timing across different islands have likely inhibited their population growth.

Photo of an australian sea lion pup sleeping on some rocks
An Australian sea lion pup snoozing. Credit: Holly Raudino.

Australian sea lions can also be caught, injured or drowned in interactions with the fishing industry. They’re further threatened by decline of their prey species, harassment on their breeding islands, and parasites such as hookworms. Luckily, medications to combat the hookworm problem in South Australian sea lion colonies are having encouraging results.

Despite being a flagship and charismatic species, the Australian sea lion’s latest population figures are concerning, with the population declining by over 60% over 40 years. The species was sadly listed as endangered under our national legislation, the EPBC Act, at the end of 2020.

This species is far more unique than a weird wet dog and is one marine mammal that deserves your vote!

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