Weddell Seal

Photograph By: Peter Rejcek, National Science Foundation

 

Description & Characteristics:

Perhaps the most well-known and 'appealing' of all the Antarctic seals, the Weddell seal lives farther south than any other mammal, inhabiting the waters of McMurdo Sound, 800 miles from the South Pole. These relatively placid animals are usually found in large groups on fast pack ice (ice attached to the continent) and can be easily approached by humans. Most of their time, however, is spent in the frigid Antarctic waters beneath several meters of ice, only emerging through cracks and blowholes to breathe, rest, and have their pups. This environment is relatively safe from other air breathing predators such as Killer whales and Leopard seals. Hunted in the past for oil, food, and skins, Weddell seal numbers are currently stable.

With their 'smiling', whiskered faces and relatively small heads, the large Weddell seals are quite appealing in appearance. After molting the adults' bodies are blue-black and spotted silver-grey, then fading to rust-brown. Their short, dense fur protects them from water temperatures as low as 28°F. Weddell seals have whiskers (called vibrissae) which enhance their sense of touch. V-shaped nostrils close when the animal is at rest. Unlike Crabeater and Leopard seals, Weddell seals are somewhat fat and not so streamlined. Females are slightly larger than males. Since Weddells use their strong teeth to chew and scrape breathing holes in the ice, extensive tooth wear occurs and is often a cause of mortality as older seals lose the ability to hunt or maintain their holes. Both male and female Weddell seals vocalize noisily underwater using a variety of calls; males may do so to maintain established territories.

Feeding mainly at night, Weddells dive to impressive depths in pursuit of fish, squid, and krill. By collapsing their lungs and lowering their breathing rates, they are able to stay underwater for up to an hour. In addition, Weddells have been observed blowing air bubbles into cracks under the sea ice to flush out prey. Like all seals, Weddells don't chew their food; they swallow it in large chunks underwater.

Weddell pups are born in colonies in September and October. Females give birth to one pup per year after reaching about six years of age. Males often defend underwater territories from other males so females can have access to breathing holes. Mothers provide pups with a rich nourishing milk (up to 70% fat) allowing the pups to gain weight quickly. Weighing up to 60 pounds at birth, by the end of the nursing period (usually 6 to 8 weeks) they have gained as much as 200 pounds. Once weaned, the pups have learned to swim, hunt, and to haul themselves out of the water and are ready to head out on their own.

 

  Did you know?



- These seals were named for the British Antarctic explorer James Weddell, who commanded British expeditions into the Weddell Sea (which is also named for him).

- Weddell seals live farther south than any other mammal.

- Weddell seals use their large, strong, forward-pointing canine teeth to chew breathing holes through cracks in the ice.

- Weddell seals have excellent eyesight allowing them to navigate effectively in the dim light beneath Antarctic ice shelves.

Weddel seals can dive over 2000 feet deep and stay submerged for over an hour.