The New Zealand Sea Lion (Phocarctos Hookeri) is monotypic of its genus and is also known as Hooker’s Sea Lion. They are the most endangered of the 5 Sea Lion species and suffered a mass mortality of unknown causes in 1998 (a year in which the el Nino effect affected several other pinniped species.) They were heavily targeted in the 19th century for their fur and oil. Hooker’s Sea Lions are listed as “vulnerable” by the IUCN and were designated as a threatened species under the New Zealand Marine Mammal Protection Act in 1997. One of the biggest concerns is entanglement and drowning in nets operated by squid fisheries as well as the species having a limited number of breeding sites. It also takes some time for adults to reach sexual maturity.
Hooker’s Sea Lions prefer to haul out and breed on sandy beaches. They are quite particular about their chosen spots and will sometimes wander as far as 2km inland. Breeding colonies tend to be established from early November through till late January.
As with many other species of pinnipeds, the bulls (beach-masters) will be the first to arrive on the scene. Here they will fight for territory and will engage in threat displays. Females arrive shortly afterwards and dominant males will gather together a ‘harem’ of between 8-25 females. Challenger and bachelor bulls will remain on the periphery, occasionally chancing their luck.
Females will give birth to a single pup which is born with light brown coat. As the pup matures, this coat will lighten if the animal is female or darken if it is a male. She will remain with her pup for the first two weeks before going off to forage. These trips last initially two to three days, but do get longer as the pup matures and becomes more self sufficient.
Pups weigh in at around 7.5kg and measure roughly 80cm-100cm at birth. Male pups tend to be slightly heavier and longer than the females. Pups begin swimming when they are as young as three weeks old and the weening process usually lasts for around 8-10 months. They are born on the beach, but after around 6 weeks, their mothers move them into vegetation.
Adult males weigh in at between 350-450kg and measure up to 3.2m in length. They will reach sexual maturity when they are around 5years, though they do not get territorial status until they are around 8. Females are much smaller than the males, weighing in at only 140-160kg and measuring around 2m in length. Females reach sexual maturity at between 3 and 4 years of age.
Males tend to live slightly longer than females, around 22 years as opposed to the females 18 years
Hooker’s Sea Lions are known among the Maori tribes as “Whakahao.”
Adult New Zealand sea Lions are able to dive repeatedly to a depth of 300m and have been known to dive as deep as 600m!
They feed mainly on a diet of squid and octopus, crabs and crayfish. The occasional fur seal and even elephant seals have been known to make for a tasty lunch. Penguins, rays and certain sea birds also form part of a varied diet. Animal infanticide has also been observed in this species, with aggressive bulls eating rival pups.
These sea lions will flick sand over themselves to keep cool as they bask in the sun. Females with small pups may even seek relief by moving far inland to use vegetation as shelter.
Females of this species will dive more often, deeper, longer and cover a greater area than any other species of seal.
These New Zealand Sea Lions are very sure of themselves. They will not hesitate to chase people or dogs. It is important to remain wary of their movements and keep a respectable distance from them.
In contrast to the dominant males as “Beach Masters” young pups are called “Beach Weaners” Not quite as flattering now is it?
Hooker’s Sea Lions are one of the largest animals to be found in New Zealand.
There have been efforts to protect this species since 1890.