Pacific Walrus(Odobenus rosmarus divergens)
Habitat and Distribution: Found primarily in the Bering and Chukchi seas. They prefer to haul out on polar ice, but will haul out on small rocky islands when ice is not available.
Size: 7.5-12 feet long; Males 1,900-5,000 pounds; females 900-2,700 pounds
Wild Diet: Primarily clams; sometimes cockles, mussels, worms, sea cucumbers, fish and seals.
Predators: Killer whales, polar bears, and humans
Lifespan: 30-40 years
Reproduction: Pacific walruses are ready to mate at 6-10 years of age. During the breeding season (December-March), males compete for a harem of females. A few older, stronger bulls usually control the majority of females. Cows generally deliver one calf every three years. The gestation period is 15-16 months, which includes a 4-5 month delayed implantation period. Newborn calves weigh 100-170 pounds and stay with their mothers for at least 2 years.Behavior: They are highly social, often found in groups of several hundred. Outside of the breeding season, males and females are often separated, but on some haul-out grounds both sexes are represented. Compact huddling when hauled out does not necessarily mean that the walruses get along--they huddle together for protection but often compete for the most favorable spots, using tusks and body size to establish and maintain social status.
IUCN Status: Data Deficient
Pacific walruses are currently being assessed for classification by the Endangered Species Act. Little recent information is available regarding current population sizes and trends throughout much of the walrus’s range, but there is some evidence of population decline. Walruses have historically been hunted for their meat, oil, ivory (tusks), bones, and hides. Overhunting severely affected population sizes in the 18th century, and although hunting restrictions have slowed the decline, the populations never fully recovered. Climate change also has negative consequences for Pacific walruses by interrupting their breeding and limiting their prey abundance. Furthermore, as Arctic ice melts, they are forced to forage in shallow coastal waters where they quickly exhaust the food supply and become more tightly packed and more prone to conflict.
Did you know?
- Walruses use stiff whiskers, called vibrissae, to feel around the ocean floor searching for clams and other tasty mud-dwellers.
- In water, walruses are pale, as blood vessels on the skin contract to protect the core against icy temperatures. On land, the blood vessels dilate and circulation increases, allowing them to lose excess heat and turning them rosy pink.