Australian fur seal

Appearance

The New Zealand fur seal is a fairly large mammal. Males have been reported to be as large as 250 kg in the literature, but the average weight is about 126 kg. Males can also grow to be 2 meters long. Females are between 30–50 kg on average, and can grow to be as long as 1.5 meters. Pups are 3.3-3.9 kg on average, and between 40 and 55 cm long. At 290 days old males are about 14.1 kg, and females are about 12.6 kg. They have external ears and hind flippers that rotate forward, which visibly distinguish them from other seals. They have a pointy nose with long pale whiskers. The fur seals are covered by two layers of fur, and their coat is grey-brown on their back, but it is lighter on their belly. Some fur seals have white tips on longer upper hairs, which can give the fur seal a silver like appearance.

Behavior

Males vocalize through a bark or whimper, either a gluttural threat, a low-intensity threat, a full threat, or a submissive call. Females growl and also have a high-pitched pup attraction wail call.

Reproduction

Female New Zealand fur seals mature between 4 and 6 years old, and males mature between 8 and 10 years old. These seals are polygynous. Males obtain and guard territory in late October before females arrive. Often females only mate once a year, and this usually occurs eight days postpartum for about 13 minutes on average. Females have a delayed implantation of the fertilized egg, so that implantation on the uterine wall does not occur for 3 months. Gestation occurs for 9 months Females are more aggressive near the time of birth, and do not like to be approached right after birth. Female New Zealand fur seals will continue to reproduce until their death which is on average between 14 and 17 years of age.

Food

Their diet includes cephalopods, fish, and birds. Stomach contents have been analyzed and shown to include anchovy, barracuda, flounder, hagfish, lamprey, red cod, school shark, and many other species. There are different factors that affect their diet, such as season, sex, breeding, surrounding colony, oceanography, and climatic patterns.

Predators

New Zealand fur seals’ known predators are killer whales, sharks, male New Zealand sea lions, and possibly leopard seals. New Zealand sea lions are also known to target pups as their prey.