Walrus: Meaning and Habitat
The walrus is a marine animal with large flippers, whiskers, and of course, tusks. A circumpolar Arctic and sub-Arctic creature, it includes three sub-species: the Atlantic walrus, the Pacific walrus, and the Laptev Sea walrus. In the northeastern Atlantic, the area in which Oceanwide Expeditions embarks on Arctic voyages, walruses are found in eastern Greenland, Svalbard, and the southern Barents and Kara seas.
The Niche Environment of the Walrus
While walruses are found across vast areas, they occupy a small ecological niche: shallow water with depths of around 80 meters (262 feet) or less, with a bottom substrate that is rich in bivalves. In addition, these shallow waters need to have reliable access to open water for feeding areas as well as ice or land so that the walruses can haul themselves out of the water. It is one of the prerogatives of Greenland cruises to make landings near these haul-out locations.
Walruses in White or Pink
While walruses are typically a cinnamon brown colour, they can turn white after diving or even pink when they are warm. This is due to their ability to vary their blood supply to the periphery of their bodies under certain circumstances. As for their dimensions, walruses are more or less uniform. They have small heads and a broad muzzle with colourless whiskers, and they can bring their hind legs up under their bodies to walk on all fours over the land.
Long (and Lifelong) Walrus Teeth
Both male and female walruses have tusks that grow continuously throughout their lives. These tusks are used as symbols of age, sex, and social status. Compared to the females, the tusks of males are much longer and wider in proportion to their bodies. The males use their tusks to show their dominance by turning their heads and thrusting their tusks in the air. Tusks are also used as weapons and can aid walruses in climbing onto ice floes from the water.
The Walrus Swimmer’s Physique
The walrus has a streamlined body that makes it easy to swim and conserve heat. Because they have a small surface-to-volume ratio along with few protruding body parts, they lose little heat. Meanwhile their forelimbs and hindlimbs are sleek and webbed, like oars. This means the walrus can go from swimming at around 5 – 6 km per hour (3 – 4 miles per hour), up to 35 km per hour (22 miles per hour) if startled. On land the walrus uses its hind limbs to get around, but it cannot use them to stand up. Instead it uses its limbs to thrust its body forwards in small lunges while hardly getting off the ground. Its thick blubber, which can be up to 15 cm (6 inches) thick, acts as a cushion when bouncing around the ice and other hard surfaces.
Shoreline or Pack-Ice Herds
Walruses are very social and are typically found in large shoreline herds or living on moving pack ice. These are the areas humans will most likely encounter them on Svalbard cruises. Walruses use pack ice as diving platforms to take short, shallow dives. Most of their dives are shallower than 50 meters (164 feet), though one Svalbard walrus was found to have dived to a depth of over 450 meters (1,509 feet). The maximum duration a walrus has spent underwater was measured at 37 minutes.
Preferred Walrus Haul-Outs
During the summer and autumn, walruses haul out on land in a few specific locations. Atlantic walruses like to haul out onto low, rocky shorelines with steep subtidal zones that provide them quick, easy access to feeding areas – as well as escape routes from predators. Pacific walruses, on the other hand, haul out on a variety of surfaces ranging from sand to boulders. These land locations are typically isolate islands, spits, and headlands.
The Walrus Weight-to-Food Percentage
Adult walruses eat between 3 – 6 percent of their total body weight per day and prefer molluscs, especially clams. They also eat other benthic invertebrates, including worms, gastropods, cephalopods, crustaceans, and sea cucumbers. At times walruses eat fish, such as the polar cod. The carcasses of young seals will also suffice when food is scarce. And while it is not common, some walruses even hunt ringed and bearded seals. These walruses are almost always sizable males with large shoulders and chest muscles.
Foraging among the Walruses
When eating a typical diet of clams and similar foods, walruses commonly forage at the bottom of the sea at depths up to 80 meters (262 feet). Most of their feeding occurs around 10 – 50 meters (33 – 164 feet). Because the water is too murky to see food, walruses rely on their sensitive whiskers to find it. Once they’ve found something to eat, they clear soft materials away from the food using their front flippers and then suck the clams out of their shells, leaving the shells on the sea floor.
Walrus Pack-Ice Birthing Rituals
About a month before giving birth, pregnant females separate from the herd and move out onto the pack ice. They birth their young in May, and afterward the mothers will remain on the ice, fasting for the first few days. During this time, they will rely on their body fat for energy. Afterwards the mothers and their young will return to the herd, and the female will start feeding properly again. Young walruses suckle on their mother’s low-fat milk for two to three years.
The Life of a Walrus Baby
Walrus pups (also known as calves) are nursed at sea, hanging upside down in the water while being cradled by their mother’s flippers. When the mother needs to dive, calves are tended to by other members of the herd. At about five months old, calves are strong enough to dive and feed on benthic organisms. Nine months after giving birth, female walruses mate again. Breeding takes place over the months of December and January, during which time males show off to females along the ice edges. Males defend these small pieces of territory, performing vocal and visual displays to attract females. Males are aggressive with one another when finding a mate, with battles often resulting in injuries. After calves are weaned, females are placed in the mother’s herd while males join male groups. Females give birth when they are around 10 years old, and males reach maturity at this time too. Walruses live for over 40 years.
5 Last-Minute Facts on Walrus Teeth, Weight, Pups, and Diet
- Walruses have two large external tusks that can grow up to a one meter long (3.28 feet) and weigh around 5 kg (11 pounds)
- Male walruses can reach 3 – 3.5 meters long (9.84 – 11.48 feet) and weigh around 1,500 kg (3,306 pounds), while females usually grow to 2.5 meters long (8.2 feet) and weigh around 900 kg (1,984 pounds)
- Calves are born weighing about 85 kg (187 pounds) and are approximately 1.3 meters long (4.26 feet)
- The male walrus is called a “bull” and has a cornified chest and shoulder area that protects it in battle
- Walruses can eat as many as 3,000 – 6,000 clams in one feeding session