Atlantic walrus - Profile | Traits | Facts | Teeth | Habitat

(Last Updated On: April 15, 2021)

The Atlantic walrus traditionally ranged from the central Canadian Arctic east to the Kara Sea, north to Franz Josef Land, and south to Nova Scotia, Canada. Six extant populations are acknowledged based mostly on their genetic interchange and different elements similar to geographical separation.

Several are shared by Canada and Greenland, and Norway and Russia share the Svalbard-Franz Josef Land inhabitants. The traditionally ample inhabitants in southeastern Canada were worn out by looking ca. 1850, and is unlikely to re-establish as a result of improvement in different human activities within the area. In this article, I am going to talk about Atlantic walrus vs Pacific walrus, sea lion with long teeth, range, habitat, baby, endangered, facts, population, etc.

Atlantic walrus Profile

The walrus, scientific name Odobenus rosmarus is a big flippered marine mammal with a discontinuous distribution in regards to the North Pole within the Arctic Ocean and subarctic seas of the Northern Hemisphere.

The walrus is the one dwelling species within the family Odobenidae and genus Odobenus. This species is subdivided into two subspecies: the Atlantic walrus (O. r. rosmarus), which lives within the Atlantic Ocean.

Adult walrus are characterized by outstanding tusks and whiskers, and their appreciable bulk: adult males within the Pacific can weigh more than 2,000 kilograms (4,400 pounds) and, amongst pinnipeds, are exceeded in size solely by the 2 species of elephant seals.

Walruses dwell principally in shallow waters above the continental cabinets, spending important quantities of their lives on the ocean ice in search of benthic bivalve mollusks to eat. Walruses are comparatively long-lived, social animals, and they’re thought of to be a “keystone species” within the Arctic marine areas.

The walrus has performed a outstanding position within the cultures of many indigenous Arctic peoples, who’ve hunted the walrus for its meat, fats, pores and skin, tusks, and bone.

During the 19th century and the early 20th century, walruses have been extensively hunted and killed for his or her blubber, walrus ivory, and meat. The inhabitants of walruses dropped quickly throughout the Arctic area.

Their inhabitants has rebounded considerably since then, although the populations of Atlantic and Laptev walruses stay fragmented and at low ranges in contrast with the time before human interference.

Atlantic walrus Description

While some outsized Pacific males can weigh as a lot as 2,000 kg (4,400 lb), most weigh between 800 and 1,700 kg (1,800 and three,700 lb). An occasional male of the Pacific subspecies far exceeds regular dimensions.

In 1909, a walrus conceal weighing 500 kg (1,100 lb) was collected from an infinite bull in Franz Josef Land, whereas in August 1910, Jack Woodson shot a 4.9-meter-long (16 ft) walrus, harvesting its 450 kg (1,000 lb) conceal.

Since a walrus conceal often accounts for about 20% of its body weight, the total body mass of those two giants is estimated to have been no less than 2,300 kg (5,000 lb).

The Atlantic subspecies weighs about 10–20% lower than the Pacific subspecies. Male Atlantic walrus weighs an average of 900 kg (2,000 lb). The Atlantic walrus additionally tends to have comparatively shorter tusks and considerably more flattened snout.

Females weigh about two-thirds as a lot as males, with the Atlantic females averaging 560 kg (1,230 lb), generally weighing as little as 400 kg (880 lb), and the Pacific feminine averaging 800 kg (1,800 lb). Length sometimes ranges from 2.2 to three.6 m (7 ft 3 into 11 ft 10 in).

Newborn walruses are already fairly massive, averaging 33 to 85 kg (73 to 187 lb) in weight and 1 to 1.Four m (Three ft 3 into 4 ft 7 in) in size throughout each sex and subspecies.

All advised, the walrus is the third largest pinniped species, after the 2 elephant seals. Walruses keep such a high body weight due to the blubber saved beneath their pores and skin. This blubber retains them heat and the fats offer energy to the walrus.

The walrus has an air sac beneath its throat which acts like a flotation bubble and permits it to bob vertically within the water and sleep. The males possess a big baculum (penis bone), as much as 63 cm (25 in) in size, the biggest of any land mammal, each in absolute size and relative to body size.

Body Shape

The walrus’s body form shares options with each sea lion (eared seals: Otariidae) and seals (true seals: Phocidae). As with otariids, it may flip its rear flippers ahead and transfer on all fours; nonetheless, its swimming method is more like that of true seals, relying much less on flippers and more on sinuous complete body actions. Also like phocids, it lacks exterior ears.

The extraocular muscular tissues of the walrus are well-developed. This and its lack of orbital roof enable it to protrude its eyes and see in each a frontal and dorsal course. However, vision on this species seems to be more fitted to the short-range.

Atlantic walrus Range and habitat

The majority of the inhabitants of the Pacific walrus spends their summers north of the Bering Strait within the Chukchi Sea of the Arctic Ocean alongside the northern coast of eastern Siberia, round Wrangel Island, within the Beaufort Sea alongside the northern shore of Alaska south to Unimak Island, and within the waters between these places.

Smaller numbers of males summer time within the Gulf of Anadyr on the southern coast of the Siberian Chukchi Peninsula, and in Bristol Bay off the southern coast of Alaska, west of the Alaska Peninsula.

In the spring and fall, walruses congregate all through the Bering Strait, reaching from the western coast of Alaska to the Gulf of Anadyr. They winter over within the Bering Sea alongside the eastern coast of Siberia south to the northern part of the Kamchatka Peninsula, and alongside the southern coast of Alaska.

A 28,000-year-old fossil walrus was dredged up from the underside of San Francisco Bay, indicating that Pacific walruses ranged that far south over the last Ice Age.

tlantic walrus Whiskers

Surrounding the tusks is a broad mat of stiff bristles (“mystacial vibrissae”), giving the walrus an attribute whiskered look. There may be 400 to 700 vibrissae in 13 to 15 rows reaching 30 cm (12 in) in size, although within the wild they’re usually worn to a lot shorter lengths on account of fixed use in foraging.

The vibrissae are hooked up to muscular tissues and are provided with blood and nerves, making them extremely delicate organs able to differentiating shapes Three mm (1⁄eight in) thick and a pair of mm (3⁄32 in) large.

Atlantic walrus Tusks and dentition

While this was not true of all extinct walruses, probably the most outstanding function of the dwelling species is its long tusks. These are elongated canines, that are present in each female and male walruses and might attain a size of 1 m (3ft 3 in) and weigh as much as 5.4kg (12 lb).

Tusks are barely longer and thicker amongst males, which use them for preventing, dominance, and display; the strongest males with the biggest tusks sometimes dominate social teams. Tusks are additionally used to kind and keep holes within the ice and assist the walrus in climbing out of the water onto the ice.

Tusks have been as soon as thought for use to dig out prey from the seabed, however, analyses of abrasion patterns on the tusks point out they’re dragged by means of the sediment whereas the higher fringe of the snout is used for digging.

While the dentition of walruses is very variable, they typically have comparatively few teeth aside from the tusks. The maximal variety of teeth is 38 with a dentition system:

3.1.4.23.1.3.2, however over half of the teeth are rudimentary and happen with lower than 50% frequency, such {that a} typical dentition contains solely 18 teeth 1.1.3.00.1.3.0.

Atlantic walrus Skin

Aside from the vibrissae, the walrus is sparsely lined with fur and seems bald. Its pores and skin is very wrinkled and thick, as much as 10 cm (4 in) across the neck and shoulders of males.

The blubber layer beneath is as much as 15 cm (6 in) thick. Young walruses are deep brown and develop paler and more cinnamon-colored as they age. Old males, specifically, turn into almost pink.

Because pores and skin blood vessels constrict in chilly water, the walrus can seem nearly white when swimming. As a secondary sexual attribute, males additionally purchase important nodules, known as “bosses”, significantly across the neck and shoulders.

Diet and feeding behavior

Walruses choose shallow shelf areas and forage totally on the ocean flooring, usually from sea ice platforms. They are usually not significantly deep divers in comparison with different pinnipeds; their deepest recorded dives are around 80 m (260 ft). They can stay submerged for as long as half an hour.

The walrus has a various and opportunistic diet, feeding on more than 60 genera of marine organisms, together with shrimp, crabs, tube worms, comfortable corals, tunicates, sea cucumbers, varied mollusks, and even elements of different pinnipeds.

However, it prefers benthic bivalve mollusks, particularly clams, for which it forages by grazing alongside the ocean backside, looking and figuring out prey with its delicate vibrissae and clearing the murky bottoms with jets of water and lively flipper actions.

The walrus sucks the meat out by sealing its highly effective lips to the organism and withdrawing its piston-like tongue quickly into its mouth, making a vacuum. The walrus palate is uniquely vaulted, enabling efficient suction. The diet of the Pacific walrus consists nearly completely of benthic invertebrates (97 p.c).

Aside from the big numbers of organisms truly consumed by the walrus, its foraging has a big peripheral influence on benthic communities. It disturbs (bioturbates) the ocean flooring, releasing vitamins into the water column, encouraging mixing and motion of many organisms, and growing the patchiness of the benthos.

Seal tissue has been noticed in a pretty important proportion of walrus stomachs within the Pacific, however the significance of seals within the walrus diet is beneath debate.

There have been remoted observations of walruses preying on seals as much as the size of a 200 kg (440 lb) bearded seal. Rarely, incidents of walruses preying on seabirds, significantly the Brünnich’s guillemot (Uria lomvia), have been documented. Walruses might often prey on ice-entrapped narwhals and scavenge on whale carcasses however there may be little proof to show this.

Atlantic walrus Reproduction

Walruses dwell to about 20–30 years old within the wild. The males attain sexual maturity as early as seven years, however don’t sometimes mate till totally developed at around 15 years of age.

They rut from January by means of April, reducing their meal consumption dramatically. The females start ovulating as quickly as 4 to 6 years old. The females are diestrous, coming into warmth in the late summer and in addition around February, but the males are fertile solely around February; the potential fertility of this second interval is unknown.

Breeding happens from January to March, peaking in February. Males mixture within the water around ice-bound teams of estrous females and interact in competitive vocal shows. The females be a part of them and copulate within the water.

Gestation lasts 15 to 16 months. The first three to 4 months are spent with the blastula in suspended growth before it implants itself within the uterus. This strategy of delayed implantation, widespread amongst pinnipeds, presumably advanced to optimize each the mating season and the birthing season, decided by ecological situations that promote new child survival.

Calves are born through the spring migration, from April to June. They weigh 45 to 75 kg (99 to 165 lb) at the start and are capable of the swim. The mom’s nurse for over a year before weaning, however, the younger can spend as much as 5 years with the moms.

Walrus milk incorporates higher quantities of fat and protein in comparison with land animals however decreases in comparison with phocid seals. This decrease fat content in flip causes a slower growth charge amongst calves and extended nursing funding for his or her moms.

Because ovulation is suppressed till the calf is weaned, females give start at most every two years, leaving the walrus with the bottom reproductive charge of any pinniped.

Migration

For the remainder of the year (late summertime and fall), walruses are inclined to kind large aggregations of tens of hundreds of people on rocky seashores or outcrops.

The migration between the ice and the seashore may be long-distance and dramatic. In late spring and summer, for instance, a number of hundred thousand Pacific walruses migrate from the Bering Sea into the Chukchi Sea by means of the comparatively slender Bering Strait.

Ecology

Commercial harvesting diminished the inhabitants of the Pacific walrus to between 50,000 and 100,000 within the 1950s-1960s. Limits on industrial looking allowed the inhabitants to extend to a peak within the 1970s-1980s, however subsequently, walrus numbers have once more declined.

Early aerial censuses of Pacific walrus performed at five-year intervals between 1975 and 1985 estimated populations of above 220,000 in every one of the three surveys.

Population

A lot of smaller inhabitants of Atlantic walruses range from the Canadian Arctic, throughout Greenland, Svalbard, and the western part of Arctic Russia.

There are eight hypothetical subpopulations of Atlantic walruses, based mostly largely on their geographical distribution and actions: 5 west of Greenland and three east of Greenland.

The Atlantic walrus as soon as ranged south to Sable Island, Nova Scotia, and as late because the 18th century was present in massive numbers within the Greater Gulf of St.

Lawrence area, generally in colonies of as much as 7,000 to eight,000 people. This population was almost eradicated by industrial harvest; their present numbers, although troublesome to estimate, most likely stay beneath 20,000.

In April 2006, the Canadian Species at Risk Act listed the inhabitants of the northwestern Atlantic walrus in Quebec, New Brunswick, Nova Scotia, Newfoundland, and Labrador as having been eradicated in Canada. A genetically distinct population existed in Iceland that was worn out after the Norse settlement around 1213–1330 AD.

Predators

Due to its great size and tusks, the walrus has solely two natural predators: the killer whale (orca) and the polar bear. The walrus don’t, nonetheless, comprise a significant factor of both of those predators’ diets. Both the killer whale and the polar bear are additionally most probably to prey on walrus calves.

The polar bear usually hunts the walrus by speeding at beached aggregations and consuming the people crushed or wounded within the sudden exodus, sometimes youthful or infirm animals.

The bears additionally isolate walruses once they overwinter and are unable to flee a charging bear on account of inaccessible diving holes within the ice. However, even an injured walrus is a formidable opponent for a polar bear, and direct assaults are uncommon.

Armed with its ivory tusks, walruses have been identified to fatally injure polar bears in battles if the latter follows the opposite into the water, the place the bear is at an obstacle.

Polar bear–walrus battles are sometimes extraordinarily protracted and exhausting, and bears have been identified to interrupt away from the assault after injuring a walrus.

Killer whales usually assault walruses, though walruses are believed to have efficiently defended themselves through counterattacks towards the bigger cetacean. However, killer whales have been noticed efficiently attacking walruses with few or no accidents.

Atlantic walrus – Profile | Traits | Facts | Teeth | Habitat | Baby