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Post by Gorilla king on Aug 5, 2021 17:37:55 GMT -5
Polar bears (Ursus maritimus) feeding on beluga whales (Delphinapterus leucas)
Abstract
Two sightings of Polar Bears (Ursus maritimus) with dead Beluga Whales (Delphinapterus leucas) on ice were made by aerial teams looking for Bowhead Whales (Balaena mysticetus) during their spring migration near Point Barrow, Alaska, from 1985 to 1992. Along with other sightings of Belugas being killed and eaten by Polar Bears reported in the literature, these records suggest that Belugas may make an important contribution to the diet of Polar Bears in some areas.
www.researchgate.net/publication/235960520_Polar_bears_Ursus_maritimus_feeding_on_beluga_whales_Delphinapterus_leucas
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Post by Gorilla king on Aug 5, 2021 17:41:30 GMT -5
Polar bears scavenge large and small whales from many sources, such as (a) a dead narwhal (Monodon monoceros) in the pack ice north of Svalbard and (b) a bowhead whale (Balaena mysticetus) harvested by indigenous subsistence hunters in Kaktovik, Alaska. Polar bears may also hunt smaller whales, such as (c) belugas (Delphinapterus leucas) in sea-ice entrapments, shown here in the Canadian Arctic.Context 1
... Large whales are the largest parcels of organic matter in the ocean • When stranded, they provide a fat-and protein-rich food source for polar bears (Ursus maritimus) • A single carcass can provide nourishment for months to years; for example, one bowhead whale carcass is nutritionally equivalent to ~1300 ringed seals • Large whales have abounded in cold oceans since the Miocene and their stranded carcasses may have facilitated polar bear survival through ice-impoverished Pleistocene interglacial periods, largely due to the polar bear's ability to quickly consume and store large amounts of lipids when available, and to then fast for extended periods • Scavenging may buffer some polar bears from the consequences of ongoing sea-ice loss; however, large whale carcasses are not expected to replace ice-breeding seals as nutritional resources for polar bears in an ice-free Arctic bears also scavenge stranded remains of large whales that died from natural causes or human-sourced mortality ( Figure 2; Herreman and Peacock 2013;Atwood et al. 2016). Despite this, there have been few attempts to evaluate the importance of large whales in the diet of polar bears or their possible role in the viability of polar bears under climate change. ...
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Context 2
... are few documented accounts of polar bears actively killing small whales, which makes it likely that predation is a learned behavior practiced by a small subset of bears and not important at the population level. Polar bears have been recorded still-hunting (lying or standing motionless while waiting for an opportunity to attack) narwhals and belugas from ice floes, the ice edge (Figure 2a), in sea-ice entrapments (Figure 2c), and river estuaries (Smith and Sjare 1990). In most cases the bear stuns or mortally wounds the whale with a powerful blow to the skull ( Smith and Sjare 1990). ...
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Context 3
... are few documented accounts of polar bears actively killing small whales, which makes it likely that predation is a learned behavior practiced by a small subset of bears and not important at the population level. Polar bears have been recorded still-hunting (lying or standing motionless while waiting for an opportunity to attack) narwhals and belugas from ice floes, the ice edge (Figure 2a), in sea-ice entrapments (Figure 2c), and river estuaries (Smith and Sjare 1990). In most cases the bear stuns or mortally wounds the whale with a powerful blow to the skull ( Smith and Sjare 1990). ... www.researchgate.net/figure/Polar-bears-scavenge-large-and-small-whales-from-many-sources-such-as-a-a-dead-narwhal_fig2_328181229
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Post by oldindigosilverback on Sept 18, 2021 7:44:08 GMT -5
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Post by Gorilla king on Sept 23, 2021 10:28:24 GMT -5
Predation of Harp Seals, Pagophilus groenlandicus, by Polar Bears, Ursus maritimus, in Svalbard
Abstract and Figures
Harp seals (Pagophilus groenlandicus) that breed in February and March in the White Sea migrate to open water around Svalbard and Franz Josef Land in the Barents Sea, feeding pelagically while following the receding ice edge northward to the edge of the polar pack. Although harp seals are present throughout the area during the summer, they are primarily pelagic and do not appear to be extensively preyed upon by polar bears (Ursus maritimus). However, occasionally, large numbers of harp seals may haul out and rest on the pack ice or feed in the water below the ice and surface to breathe between the floes. When approached by a polar bear while on the ice, harp seals do not exhibit the instant flight response characteristic of the polar bear’s primary prey species, ringed (Pusa hispida) and bearded seals (Erignathus barbatus). In this situation, polar bears may make multiple kills without either consuming their own prey or scavenging seals killed by other bears. This behavior appears not to frighten other nearby harp seals, whether hauled out on the ice or in the water below the floes. These unusual concentrations of harp seals hauled out on sea ice may be related to the distribution and abundance of fish or other epontic prey. Their lack of an escape response to predators on the surface of the sea ice is probably a result of briefly hauling out in large numbers in spring while whelping on the sea ice in areas where the consequences of potential polar bear predation are insignificant. The rare events of harp seal mortality from bears killing them on the surface of pack ice during the summer do not appear to have a significant impact at the population level of either species.
A single polar bear killing several harp seals that were hauled out on the pack ice at 80º36.33′ N, approximately 70 km north of the Svalbard coast.www.researchgate.net/publication/333909375_Predation_of_Harp_Seals_Pagophilus_groenlandicus_by_Polar_Bears_Ursus_maritimus_in_Svalbard
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Post by oldindigosilverback on Sept 25, 2021 22:27:18 GMT -5
Some information regarding polar bear interactions with muskox, a smaller but still large bovid: "Only on rare occasions have bears been reported to threaten or kill muskoxen. Hone (1934) reported the probable killing of an old bull by a polar bear in Germania Land in East Greenland. This appears to be the only reported instance of such predation." Source: TENER, J.S. 1965. Muskoxen in Canada: A Biological and Taxonomic Review. Canadian Wildlife Service Monograph 2. 166 p. "The muskox has only 2 natural predators in northeast Greenland, the polar bear (Ursus maritimus) and the arctic wolf (Canis lupus). Throughout northeast Greenland polar bears are common, and there are several observations of adult polar bears attacking and killing muskoxen, most often lone adult bulls (J. Danielsen, pers. comm.; F. Kristoffersen, pers. comm.; T. Larsen, pers. comm.)." "Polar bears and arctic wolves are absent in central west Greenland. The introduced muskoxen around Sondre Stromfjord therefore live in an area without natural predators." Source: STATUS OF THE MUSKOX IN GREENLAND HENNING THING, 1984. Game Biology Station, Kate, DK-8410 Ronde, Denmark POUL HENRICHSEN, Zoological Museum, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen 0, Denmark POUL LASSEN Game Biology Station, Kate, DK-8410 Ronde, Denmark. Source: Polar Animals, 1958. From the discord. Credited to another poster.
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Post by oldindigosilverback on Sept 25, 2021 22:31:13 GMT -5
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Post by oldindigosilverback on Sept 25, 2021 22:34:39 GMT -5
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Post by oldindigosilverback on Sept 28, 2021 12:00:13 GMT -5
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Post by oldindigosilverback on Sept 28, 2021 12:02:55 GMT -5
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Post by Gorilla king on Sept 29, 2021 6:43:01 GMT -5
POLAR BEAR PREDATION OF CARIBOU IN RUSSIA:
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Post by arctozilla on Nov 23, 2021 15:48:18 GMT -5
According to National Geographic polar bears do view huskies as extra food. “Being intelligent and amazing, polar bears have learned to associate dogs with extra food, and have realized that without dogs, there is no food. Thus, the bears do not kill the dogs.” She likens it to how orcas have been known to toss seals around before deciding whether to return them to land or eat them.30 gen 2018 www.nationalgeographic.com/animals/article/polar-bear-plays-with-dog-churchill-manitoba-spd
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Post by arctozilla on Dec 1, 2021 17:12:57 GMT -5
March 1970 Canadian Arctic Milton M. R. Freeman reports subadult female bear killing 2 adult female belugas 5x her size and dragging them out of water. During May 1970, while conducting field work at Grise Fiord in the Canadian Arctic Archipelago, a local hunter reported that a polar bear (Ursus maritimus) had successfully caught 3 beluga (Delphinapterus leucas) during March near King Edward VII Point (76°08'N., 81°08' W.), the extreme southeast cape of Ellesmere Island, Northwest Territories. As none of the fifteen local hunters had ever witnessed such an event, and only one had ever heard of it before, I assumed bear predation on whales to be very rare, and consequently recorded whatever information I could obtain at the time. According to the hunter's narrative, movement of a partially grounded iceberg about 200 meters offshore had prevented freezing of a small area of water surrounding the berg. Winter trapment of whales is known to occur during unusual conditions of sea-ice formation1, and as the open sea was at least 30 kilometers distant from this locality in March it seems probable that a small number of beluga had endeavored to pass the winter in the open water alongside this berg. At some time in March a medium-sized female bear had caught and removed an adult female beluga together with another adult and a grey-colored sub-adult beluga both of unspecified sex; the adult female beluga was dragged about 7 meters from the edge of the water, the other two a shorter distance only. Inspection of the carcass indicated loss of all skin and fat, and most of the meat from head and trunk; fracture of the occipital bones had occurred, but it is not known if this damage was suffered before or after death. An eyewitness account of a polar bear killing beluga in Novaya Zemblya however, relates how the bear lies with outstretched paws on the ice and delivers a blow to the head when the whale surfaces within range. In this region of the Canadian Arctic Archipelago, beluga generally change color from grey to white at around 375 cm. in length. 3 Assuming the two white-colored beluga were around 400 cm. in length, their weight is calculated to be about 935 kilograms4; the grey-colored sub-adult measured 275 cm. and had a computed weight of 350 kilograms. There appears no reason to doubt that the hunter reporting this event had, as he believed, discovered the beluga shortly after they were caught in March, nor that the tracks of the medium-sized female bear near the carcasses at that time were those of the predator. According to the description given, such a bear would weigh in the range of 130 to 180 kilograms, or about one-fifth the probable weight of each adult beluga it had successfully killed and removed from the water. Source: Freeman, M. Polar Bear Predation on Beluga in the Canadian Arctic, ARCTIC, Vol 26, No 2 (1973), p.163-163 (PDF LINK) journalhosting.ucalgary.ca/index.php/arctic/article/view/65963
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Post by Gorilla king on Dec 1, 2021 17:23:02 GMT -5
Reply #31, great find there arcto!
The incredible detail is that a subadult female did this.
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Post by arctozilla on Dec 1, 2021 17:33:06 GMT -5
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Post by arctozilla on Dec 2, 2021 4:18:18 GMT -5
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Post by arctozilla on Dec 2, 2021 7:49:03 GMT -5
/\ BTW Montezuma also confirms the post at reply #6.
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Post by Gorilla king on Dec 2, 2021 8:39:36 GMT -5
/\ BTW Montezuma also confirms the post at reply #6. Nice accounts bro. It also has to do with the original post of this thread, the event that took place at the location Novaya Zemlya.
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Post by arctozilla on Dec 2, 2021 13:14:30 GMT -5
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Post by arctozilla on Dec 2, 2021 13:26:37 GMT -5
To conclude the account at Reply #50 I can tell you the whales were adults. Here's an article mentioning the same incident... "In this case, the victims were whales — more than 40 belugas and at least one bowhead — which presumably had swum west from Baffin Bay during a warm spell in early spring and become entrapped when conditions changed. Now, they were keeping their breathing holes open as they surged to the surface for air. Until the ice broke up, they would be prisoners in this spot, unable to stray from their oxygen source. Meanwhile, the trapped whales attracted the bears, which may have detected them through their super-keen sense of smell. The bears backed away when the helicopter set down near one of the ponds, but signs of their depredations were everywhere. Many of the whales in the water had been bitten and clawed, and eight dead belugas were sprawled along the margins of the ponds where, apparently, they had been dragged by the bears. (How does a quarter-tonne bear lift a tonne of dead weight? "Polar bears are very strong" is the best that Ramsay can say.[/b])" CANADIAN GEOGRAPHIC NOVEMBER/DECEMBER 1999 ► www.canadiangeographic.ca/magazine/nd99/curious.asp► www.canadiangeographic.ca/wildlife-nature/articles/pdfs/polar-bear-polar-bear-banquet.pdfNote: it is mentioned the beluga whales weighed "one ton" which means those were of course adults.
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Post by Gorilla king on Dec 2, 2021 13:37:47 GMT -5
Seems more like subadults, but better scientific data on weights is needed. Anyways, the weights listed here seem like the max, not the average.
Size
Adults average 3 m (9.8ft) in length.
Males average 3.4–4.6 m (11.2–15.1 ft) and weigh about 1,500 kg (3,307 lbs.).
Females average 3–4 m (9.8–13.1 ft) and weigh about 1,360 kg (2,998 lbs.).
Beluga whales reach full size at about 10 years.
seaworld.org/animals/all-about/beluga-whales/characteristics/
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