Weddell seal

The Weddell seal (Leptonychotes weddellii) is a relatively large and abundant true seal. It lives in areas surrounding Antarctica, especially around the Southern Ocean known as the Weddell Sea. This seal was discovered and named in the 1820s by British sealing captain James Weddell during his expeditions.

Weddell seals are special because they live on the fast ice close to the Antarctic continent. This makes them easy for scientists to study, as they are often near research bases. They are the only species in their genus, called Leptonychotes.

Description

Weddell seals are large seals, measuring about 2.5 to 3.5 meters long and weighing between 400 and 600 kilograms. They have bulky bodies and short fore flippers. Males are usually a bit lighter than females but may have thicker necks and broader heads.

These seals have thin fur covering most of their bodies, with some areas around the flippers being bare. Their fur color changes with age and season, ranging from bluish-black on the back to lighter grey or silver on the belly. Baby seals, called pups, are born with a soft, fuzzy coat that changes color after a few weeks. Pups start at about half their mother's length and grow quickly, gaining about 2 kilograms each day in their first few weeks of life.

Behaviour

Weddell seals are often seen on ice that is stuck to land, called fast ice. They like to gather in small groups around cracks and holes in the ice. During winter, they stay in the water to avoid heavy snowstorms, only sticking their heads up through holes in the ice to breathe. These seals stay in one place and move around the ice as it changes with the seasons.

When looking for food, Weddell seals dive deep into the water. They can dive up to 600 meters deep and stay underwater for about an hour. They mainly eat fish, small sea creatures, and squid. Even though they usually don’t eat birds, sometimes they have been seen chasing and catching penguins.

Weddell seals return to the same icy areas each spring to have their babies and mate. Most of the time, they have one baby each year, but sometimes they can have two. The babies are born on the ice and can swim about two weeks after they are born. Mothers and babies recognize each other by smell and special sounds at first. The seals start mating when they are about six to eight years old.

These seals talk to each other using different sounds. Males sometimes make trilling sounds, and both males and females can make songs that repeat the same notes. Babies make special higher-pitched sounds when they are hungry to call their mothers.

Taxonomy

In the past, the name of the Weddell seal was written incorrectly, but scientists now use the correct spelling. Sometimes, people still see the old, wrong spelling in old science books.

Weddell seals look similar to two other seal types that live in the same area: the Ross seal and the crabeater seal. It's important to tell them apart.

Population status

Weddell seals are the second most abundant seal species in Antarctica, after the crabeater seal.

The latest estimates suggest there are about 202,000 female Weddell seals. These numbers come from detailed satellite images taken in November 2011, covering all areas where the seals live. This count includes only females because males are mostly underwater protecting their areas during that time. There are probably fewer male seals than females.

Earlier guesses, which did not cover as much area and relied more on predictions, often said there were around 800,000 seals. Counting these seals is hard and costly because they live in wide areas, so it is not done often. However, better satellite images and help from many people might make future counts easier with computer programs.

Threats

During early Antarctic exploration, Weddell seals were hunted for food and oil, which caused their numbers to drop sharply. Luckily, their populations have grown again since commercial sealing stopped in the 1980s.

Today, scientists are watching how climate change might affect these seals. Changes in temperature can change the sea ice and food supply, which might make it harder for baby seals to survive. Some seals live on land in places like South Georgia, showing they can adapt, but more research is needed.

Research bases in Antarctica used to bother the seals, but rules now protect the area from harmful activities like mining and oil drilling. However, more tourists visiting Antarctica might still affect the seals' behavior and where they live, though scientists are still studying this.

Right now, there aren’t many problems between seals and fishing, but new fisheries, especially for Antarctic toothfish, could change that, so careful planning is important.

Conservation status

The Weddell seal is protected by the Antarctic Treaty and the Convention for the Conservation of Antarctic Seals. It is considered to be of "least concern" by the IUCN. This species is not listed by CITES.