Marine Mammals
Atlantic Walrus
Odobenus rosmarus rosmarus
ALSO KNOWN AS
Walrus
DISTRIBUTION
Eastern Arctic
ECOSYSTEM/HABITAT
Shallow (80m or less), open water areas with soft sea floors close to land or pack ice
FEEDING HABITS
Foraging predator
TAXONOMY
Order Pinnipedia (seals, sea lions and relatives); Family Odobenidae (walruses)
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The Atlantic walrus is one of the most iconic marine mammals of the Arctic, thanks to its large, ivory tusks. These tusks are actually elongated canine teeth. Both males and females have them, although the males’ tusks are much longer. Walruses are very large: adult males weigh between 1,000 to 2,000 kilograms. Because of their size, they are rather clumsy and slow-moving on land, but in the water they have smooth and graceful swimming abilities.
The Atlantic walrus is one of the most iconic marine mammals of the Arctic, thanks to its large, ivory tusks. These tusks are actually elongated canine teeth. Both males and females have them, although the males’ tusks are much longer. Walruses are very large: adult males weigh between 1,000 to 2,000 kilograms. Because of their size, they are rather clumsy and slow-moving on land, but in the water they have smooth and graceful swimming abilities.
Walruses are most easily identified by their large front tusks, which are longer and wider on males than on females. They also have a moustache-like array of whiskers around their mouth, which is used for sensing prey hidden in the seafloor. Both their front and hind limbs have developed into flippers, with the front flippers able to support their body weight. They have thick skin that is a cinnamon-brown colour, which may appear more pink on a hot day or white-ish after a long dive. Walruses can grow to around three metres long and weigh from 800 kilograms for females to up to almost 2,000 kilograms for males.
Walruses mate from late February to April; however little is known about their reproduction because they mate in the water – something that has proven nearly impossible to study. Males will chose and defend territories in the water, rather than on land. Fighting will occur between males over access to females and control of their territories. Males reach sexual maturity between seven and 13 years of age, while females reach maturity between five and 10 years of age. Females only give birth to a pup approximately every two to three years. Females will haul out on land to give birth to pups, either on pack ice floes or nearby land, congregating on these haul-out sites. The relationship between a female and her pup is very strong: mothers are very protective, nursing their young for 25 to 27 months. The bond between mother and pup continues during and after weaning, with females teaching their young how to dive and forage for prey. Walruses eat bivalve molluscs, such as clams, but they will also root around in soft sediment bottoms for other small invertebrates and fish that live in and on the ocean floor. They likely use their sensitive whiskers to find food, unearthing prey with their snout.
Walruses were heavily hunted for their ivory and blubber, especially throughout the 17th and 18th centuries. The Gulf of Saint Lawrence population, called the Northwest Atlantic or Maritime population, was hunted to “extirpation” by the end of the 18th century, meaning they can no longer be found in this area. They continue to be hunted by Inuit and other Indigenous People in northeastern Canada today as a traditional source of food and other products, with hunts co-managed by the Nunavut Wildlife Management Board and Fisheries and Oceans Canada. There is also a small sport hunting industry for walrus, for which hunters must have a license.
Walrus aren’t thought to be directly affected by Greenland halibut and northern shrimp fisheries in the Arctic, but they can be scared by noises on land or underwater from fishing activity. When this happens, walruses can abandon sites, potentially preventing successful reproduction. With decreasing levels of sea ice in the Arctic and more human activity, walruses will increasingly interact with fisheries. Further research is needed to better understand the affect this will have and how best to protect them.
Atlantic walrus living in Canada’s Arctic were assessed in 2006 by the Committee on the Status of Endangered Wildlife in Canada as of Special Concern. They were given this designation due to decreases in populations caused by hunting throughout the 17th to 20th centuries and due to their limited recovery, since they only reproduce every two to three years. There is not sufficient research on Canadian Atlantic walrus populations to assess them any further than warranting special concern. Walruses have very specific habitat requirements, restricted seasonal distributions and rely on sea ice for successful reproduction. Increasing human activity in the Arctic and the impact of climate change will limit their chances for recovery. The Northwest Atlantic or Maritime population is considered Extirpated due to overhunting in the 17th and 18th centuries. There are occasional sightings of walruses in these areas but an established population no longer exists.
