Morse
Le mammifère marin emblématique à défenses de l'Arctique
Ce qu'il faut savoir sur : Walrus
Our Expert Says… "WIth their tusks up to 1m in length, these animals were very important as a source of ivory for Viking and indigenous arctic peoples. We still don't know what they use the tusks for, but it's certainly not for feeding or defense. The Svalbard population, after a slow start post-protection, is now doing really well."
The walrus is one of the most iconic of the arctic marine mammals. With their large tusks and long whiskers, the adults make a striking sight hauled up on the pack ice. Second only to the elephant seal in size, adult male walrus can weigh as much as 1,800kg (4,000lbs), although more typically they are between 900kg and 1,400kg (2 to 3,000lbs). The walrus has a remarkably thick hide. It’s so dense that it can account for about 20% of an animal’s total body weight.
There are 2 sub-species of walrus, the Atlantic, and the Pacific. The Pacific walruses are larger, typically around 20% bigger than the Atlantic walrus. Despite their size, walrus prefer shallow waters, and they can often be seen diving from ice floes to hunt in the soft sediments of the sea bottom for mollusks. Their favorite food is clams, but they are quite opportunistic feeders and will take other mollusks, crabs, shrimp, and sea cucumbers.
They hunt using their sensitive whiskers to locate prey, and because of their preference for shallow diving, they can stay underwater for up to 30 minutes at a time. Because of their huge size, walruses are only in danger from 2 predators - orcas and polar bears. The walrus is a powerful animal, however, and polar bears will target walrus calves or injured walruses more than they target healthy adults. Orcas, however, may sometimes target young animals in the water and are usually successful in their attacks.
The walruses calve during their spring migrations between April and June. A calf can weigh up to 165lbs and they can swim from birth. They grow slowly compared to other marine mammals, typically taking over a year to wean. The females don’t mate until the calf is weaned, meaning that they typically give birth only once every 2 years. In the summer and fall, walruses tend to congregate in huge numbers on rocky beaches until the sea ice begins to form again.
Walruses played an important part in the lives of several native arctic peoples. As well as hunting them for meat their tough hides were used for making houses and canoes, their tusks for tools and engraved art, and their blubber rendered into oil used for light and heat. The walrus is still important to some native peoples for meat and tusk engraving.
In the 18th and 19th centuries, the Atlantic walrus was almost wiped out by commercial hunting. Although now protected from large-scale commercial exploitation, large numbers of walruses are taken each year by indigenous peoples and there is some concern about their vulnerability given the effects of climate change and their low reproduction rate. Walruses rely on good levels of pack ice to give birth and to come together to mate, and the reduction in ice levels over recent years could have an impact on the species.
Walrus : Photos & Vidéos
