Weddell seals grow to 10 feet in length and weigh over 1,000 pounds; there is little difference in body size between the sexes. Their heads are proportionately small, their dark bodies patterned with silver marks. In distribution they are circumpolar in Antarctica coastal waters.
Weddell seal pups are born during austral spring, from September to November, mostly in maternal colonies where seals "haul out" to fast ice (the relatively stationary shelf attached to the coastline). Female seals usually birth a single pup, weighing around 60 pounds.
Pups grow quickly; when they are weaned after six or seven weeks, they weigh roughly 275 pounds. They enter the water within two weeks of birth.
Adult male Weddell seals defend underwater territories in proximity to fast ice haul-outs, sometimes engaging in violent disputes. Adult males and sub-adult, nonbreeding seals rarely frequent the pupping colonies. After pups are weaned, females enter the water to replenish weight lost during nursing and to mate; delaying embryo implantation ensures a birth the next spring. Adults molt after mating.
Weddell seals stay fairly faithful to coastal ice, making impressive dives of up to almost 2,000 feet in pursuit of fish like Antarctic cod. Migrations are rare and erratic, usually undertaken by juveniles. Nonetheless, widely traveling Weddells sometimes appear well north of their usual range off Australia, New Zealand and the far southern coast of South America.
