Phocarctos hookeri
New Zealand sea lion

These sea lions inhabit the subantarctic islands of New Zealand, between latitudes 48 and 53 degrees S. Their population distribution is centered on the Auckland Islands.

New Zealand sea lions inhabit the sandy beaches of New Zealand and its surrounding islands. The pups explore freshwater creeks and pools behind the beach for about their first six months, until their mothers introduce them to the sea. When not in the sea or on the beach, the sea lions can be found resting deep in the forest or on the tops of grass covered cliffs.

New Zealand sea lion pups are born covered with thick, dark hair. It is unknown when they lose this natal coat. Adult males become dark blackish-brown with a well-developed mane reaching to their shoulders. Females have lighter coloration, generally buffy or grey with a lighter ventral side. They may have darker pigmentation around their flippers and muzzle. There is marked sexual dimorphism, also, in size of males and females. Males reach a maximum length of up to 350 cm, while females reach a maximum length of up to 200 cm. Males may weigh as much as 410 kg and females as much as 230 kg.

Dental formula is usually I 3/2, C 1/1, cheekteeth 6/5.

Adult males flock to breeding beaches between October and early November in order to claim their territories. Pregant females arrive one month later. Cows come into estrus six to seven days after giving birth and matings take place from mid December to mid January. Most copulations take place on the sandy beach. Copulation ends when the cow bites at the throat of the bull.

All births take place on the beach. Most births produce only one pup. The pup is nursed by its mother for about a year. Females produce their first pup around age four. Males become sexually mature around age five, but they do not mate until they are around eight years of age.

New Zealand sea lions are generally calm creatures. Social hierarchies are restricted to subadult and juvenile males. Only these males are able to establish territories, so the conflicts among these males usually occur when defending territories. Adult males are very intolerant of other adult bulls, but they are much more tolerant of the juvenile males and homosexual mounting between the two has been observed. Adult females congregate in large groups on the beach during breeding season. Cows break off into groups of about thirty individuals and depart for the sea. Cows are very tolerant of other females and of their pups.

The New Zealand sea lions feed on octopus, small fish, crabs, mussels, and penguins. They swallow pebbles (gastroliths) to aid in digestion. Their intestines may contain numerous gastroliths of irregular shapes. They vomit these gastroliths, as many as 20 at a time, along with squid tentacles and small fish. These sea lions will not leave their territory to feed during the breeding season. They have learned to follow fishing vessels and take advantage of discarded or escaped fish.

New Zealand sea lions once provided man with hides, meat, and oil.

There are, at most, between 3000 and 4000 New Zealand sea lions in existence. They were abundant at their time of discovery in 1806, but their numbers quickly diminished. They were exploited by settlers and shipwrecked sailors for their hides and oil. Although they have been protected by law since 1894, their numbers have remained unchanged in 70 years.