| Class: | Mammalia |
| Order: | Carnivora |
| Family: | Odobenidae |
| Size: | Length: Up to 10 feet (3 m) |
| Weight: | 882 to 375 pounds (400 to 1700 kg) |
| Diet: | Mussels, snails, crabs, worms, fish and other soft-bodied animals |
| Distribution: | Coastal regions of the Arctic |
| Young: | 1 calf every 2 or more years, depending on the age of the female |
| Animal Predators: | Polar bears and killer whales |
| IUCN Status: | No special status |
| Terms: | Male: Bull Female: Cow Young: Calf |
| Lifespan: | 16 to 40 years in the wild |
·
Walruses spend about two-thirds of their lives in the
water.
·
As walruses
age, their skin becomes paler.
· Northern cultures are allowed by law to hunt walruses for subsistence living.
· The name “walrus” originated with the Danish word “hvalros,” meaning “sea horse” or “sea cow.”
· The age of a walrus can be determined by the number of rings found in a cross-section of their tooth.
Both males and females have tusks, but those of the male are longer, straighter and heavier, reaching lengths of up to 39 inches (1 m). The tusks are used for fighting and also for pulling themselves out of the water onto an ice floe. Walruses have greyish-brown, nearly hairless skin that gets paler when they enter cold water and turns red when they sunbathe. The limbs are modified into flippers. The hind flippers can be brought underneath the body and are used for terrestrial location, which is very slow. Walruses have no external ears and small eyes. Male are larger than females.
Walruses live in the coastal waters of the northeastern Canadian Arctic and Greenland east to Novaya Zemlya; the Bering Sea and adjacent Arctic Ocean; the Laptev Sea, north of Siberia; the northwestern coast of Alaska; northern Norway; and Ellesmere Island. Walruses migrate up to 1,863 miles (3,000 km) south when the Arctic ice expands and return north when the ice recedes. Their primary mode of migration is swimming, but they may also ride ice floes. They usually can be found where the water is less than 262 feet (80 m) deep, with a stony bottom, and where the air temperature is below freezing, from -15 to +5°C (5 to 41°F).
They eat animals that live on the ocean’s bottom, such as mussels, snails, crabs, worms, fish and other soft-bodied animals.
Mating takes place in January and February when the males gather in groups to attract females. The courtship is quite an impressive display, with the males making underwater vocalisations that resemble singing and bell-like sounds, then raising their heads out of water to cluck and whistle. Males will fight with each other if they are interrupted during their courtship rituals, with the fight ending when one bull gives in and leaves. After mating season, the bulls return to their all-male herds. Implantation is delayed for four to five months, making the amount of time between conception and delivery 15 to 16 months. Just before giving birth, a female will leave her herd, and join another herd of mothers and offspring a few days after her calf is born. The females in the new herd help each other with their offspring and even adopt orphaned calves. A newborn calf weighs approximately 99 to 165 pounds (45 to 75 kg) and can swim right away. Mothers are extremely affectionate with their young, as well as fiercely protective. A female will hold her calf against her chest, between her fore flippers, when danger is near. Calves often ride on the mother’s back while in the water. Nursing continues up to two years of age or longer if the mother does not give birth again within that time, although calves learn to find food well before they are weaned. Calves’ tusks begin to appear during their first year. Young males leave their mother’s side sometime between two and three years of age to go join an all-male herd. They do not become sexually mature until eight to 10 years, and probably will not be able to successfully compete with other adult males until they reach 15 years of age. Females stay with their mother’s herd for life, and are able to reproduce sometime between six and seven years of age.
Walruses are gregarious and social animals, living in herds of hundreds or even thousands. When on land or ice floes, they lie in close physical contact with each other. The leaders of the herd are the biggest, most aggressive walruses with the largest tusks. Walruses with small or broken tusks have a low social ranking. The choicest spot is in the centre of the herd, and the larger walruses will take away a spot inhabited by a smaller, weaker walrus by scaring him with his tusks. Males and females live in separate herds, only mixing during mating season. Walruses swim at approximately four miles (7 km) per hour but can go as fast as 22 miles (35 km) per hour for short distances.
COSEWIC (Committee on the Status of Endangered Wildlife in Canada) lists the Northwest Atlantic population as Extirpated, with the main cause being overhunting. Walruses have been protected in Canada since 1867. Commercial walrus harvests were banned in the United States in 1941 and in the former Soviet Union in 1992.
http://animaldiversity.ummz.umich.edu/accounts/odobenus/o._rosmarus$narrative.html
http://www.speciesatrisk.gc.ca/Species/English/SearchDetail.cfm?SpeciesID=128
http://www.absc.usgs.gov/research/walrus/man.html
http://www.mnh.si.edu/arctic/html/walrus.html
http://www.seaworld.org/infobooks/Walrus/home.html
http://www.pinnipeds.fsnet.co.uk/species/walrus.htm
http://www.nature.ca/notebooks/english/walrus.htm
Walrus Wildlife Fact File, IM Pub, US
Vaughan, T., Ryan, J. and Czaplewski, N. (2000). Mammalogy, Fourth Edition. Orlando: Saunders College Publishing