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AUSTRALIAN, NEW ZEALAND SEA LIONS

IDENTIFICATION: Males reach 8–10 feet in length and have a massive neck, shoulders, and mane; females are smaller. DISTRIBUTION: Southern coast of Australia; South Island of New Zealand and other subantarctic islands to the south; New Zealand species is vulnerable. HABITAT: Coastal waters and adjacent shores. STUDY AREAS: Dangerous Reef Island, South Australia; Enderby Island, Auckland Islands, New Zealand.

NORTHERN FUR SEAL

IDENTIFICATION: A dark brown or gray seal with extremely dense fur, large flippers and a relatively small head; females reach 41/2 feet in length, males nearly 7 feet. DISTRIBUTION: North Pacific waters; vulnerable. HABITAT: Oceangoing; breeds onshore. STUDY AREAS: St. Paul and St. George Islands, Pribilof Islands, Alaska.

Social Organization

During the breeding season, females of each of these species aggregate into groups among which a smaller number of males are distributed. This organization has been mistakenly interpreted as a “harem” structure, when in fact males have little control over the movements of the females, whose grouping is often the result of seeking each other out while simultaneously avoiding males. In the Northern Fur Seal, nonbreeding animals and juveniles gather on islands separate from the breeding areas; nonbreeding groups also occur in the other two species. Outside of the mating season, Australian and New Zealand Sea Lions form smaller mixed-sex groups, while Northern Fur Seals are oceangoing, relatively solitary, and sex-segregated during the fall, winter, and spring.

Description