Cape Fur Seals at Seal Island
Cape Fur Seals are intensely curious animals, using their large, well developed eyes and sensitive mouths to investigate virtually everything in their environment. But when White Sharks are about, such curiosity is abandoned and all eyes search anxiously beneath the surface.
Seal Island is populated by approximately 60 000 Cape Fur Seals. Adult male Cape Fur Seals are up to 2.7 meters in length and 350 kilograms in mass. They usually mature at about 3 years, but generally do not become large and powerful enough to defend breeding territories until around 10 to 14 years of age. Experienced bulls often attempt to reclaim the same breeding territories they held the previous year.
Adult females are less than 2 meters and 100 kilograms in mass. Females mature at 2 to 3 years of age.
In late October, the adult males come ashore on Seal Island to compete for and establish breeding territories, followed shortly thereafter by the adult females. Gestation period is around 11.5 months. Pups are born on Seal Island between mid-November and mid-December. Cape Fur Seals pups measure about 75cm long and 5 to 6 kilograms.
The pups suckle for almost a full year, although they begin taking solid food at an age of about 6 months. Around 2,000 Cape Fur Seals pups are born each season but, before their first year, a large percentage drown, fall victim to infection, or are crushed by adult males. As a result, for several weeks each summer, hundreds of dead seal pups are found floating in the waters around Seal Island.
Adult male Cape Fur Seals compete noisily and violently to establish a breeding harem of about 20 adult females. Successful bulls mate with their harem of cows about six days after the pups are born. Adult seals may spend as much as half of each year at their rookery.