1. Birth: Elephant seals are born on rookeries, which are designated breeding grounds near coastlines. Elephant seal pups weigh approximately 66-77 lbs (30-35 kg) and are about 3-4 ft (1 m) long. After giving birth, the mother seals nurse the pups for several weeks on a high-fat milk, enabling the pups to gain weight rapidly (up to 4.6 lbs per day) and develop a thick layer of blubber.
2. Weaning and Molting: At around 3-4 weeks old, elephant seals undergo weaning as the mothers gradually stop nursing them. During this time, the pups lose their lanugo (soft fetal fur) and go through a molting process, developing a waterproof outer layer of fur that allows them to swim in the ocean.
3. Juvenile Phase: After weaning, the pups transition to a juvenile phase where they learn how to swim, dive, and hunt. They spend several months in the ocean, often traveling long distances, as they gradually develop the skills needed to survive in the marine environment.
4. Sub-Adult/Yearling Phase: As elephant seals approach one year of age, they return to the rookery to rest, molt again, and store body fat in preparation for their first long migration. During this time, they do not feed and rely solely on their accumulated energy reserves.
5. Long Migration: After the yearling phase, elephant seals embark on extensive migrations, traveling thousands of kilometers across the ocean. They undertake these journeys in search of food and mates. Some species, such as the northern elephant seal, undertake one of the longest migrations of any mammal, traveling as far as Alaska to Mexico and back.
6. Breeding and Maturity: Elephant seals reach sexual maturity at different ages depending on the species. Male elephant seals, called bulls, mature at around 3-5 years, while females, called cows, mature at around 3-6 years. During the breeding season, bulls arrive at the rookeries and establish territories. Cows arrive later, and the bulls engage in fierce battles to compete for mates. Dominant males defend their harems of several cows, mating with multiple females.
7. Molting and Resting: After the breeding season, elephant seals undergo a molting process once again, shedding their outer fur to replace it with a new coat. During this time, they refrain from feeding and rely on stored body fat for energy. They may spend several weeks or months on land before returning to the ocean.
The lifecycle of an elephant seal is marked by cycles of feeding, breeding, molting, and long-distance migrations, with each stage playing a crucial role in their survival and reproductive success.