The Weddell Seal (Leptonychotes weddellii), a "true seal", is named after Sir James Weddell, commander of British sealing expeditions in the Weddell Sea. They occur in large numbers and inhabit the circumpolar region of the southern hemisphere, including Antarctica. It is estimated that there are currently 500,000 to one million or more of these animals today. They can regularly be seen in the many seasonally ice-free islands along the Antarctic Peninsula. These pinnipeds are not thought to migrate, and any local movements are usually the result of changes in ice conditions.

Behavior and Ecology

Weddell Seals are known for their very deep dives -- which may reach some 700 meters. They can also hold their breath for approximately 80 minutes. Such deep dives involve foraging sessions, as well as searching for cracks in the ice sheets that can lead to new breathing holes.

Depending on the latitude they inhabit, these marine mammals give birth from early September through November, where lower latitude means earlier pupping. They are not very social out of water, even avoiding physical contact at most times. It is of no surprise, then, that copulation has been observed occurring only underwater, where the female is often times bitten in the neck by her partner. Young Weddell Seals have gray pelage for the first 3 to 4 weeks, after which time, they turn to a darker color. Play fighting is very common for these animals as they grow. The pups reach maturity at 3 years of age.

Prey and Predators

The diet of the Weddell Seal consists of squids, notothenid fishes , as well as Antarctic toothfish up to 54 kilograms in weight. The Weddell Seal's predators include Killer Whales and Leopard Seals. These animals are also killed by man to supply the dog food market.

Due to the high number of parasite infections, the remains of these animals are commonly used for studying parasite and worm infestations. Weddell Seals regularly expunge their parasites by means of regurgitation.

Protection

The Weddell Seal is protected by the Antarctic Treaty and the Convention for the Conservation of Antarctic Seals.

References

1. OBIS-SEAMAP
2. ADW: Leptonychotes weddellii