+- WildFact (https://wildfact.com/forum)
+-- Forum: Information Section (https://wildfact.com/forum/forum-information-section)
+--- Forum: Terrestrial Wild Animals (https://wildfact.com/forum/forum-terrestrial-wild-animals)
+---- Forum: Carnivorous and Omnivores Animals, Excluding Felids (https://wildfact.com/forum/forum-carnivorous-and-omnivores-animals-excluding-felids)
+----- Forum: Bears (https://wildfact.com/forum/forum-bears)
+----- Thread: Grizzly Bears are Intruding into the Territory of Polar Bears (/topic-grizzly-bears-are-intruding-into-the-territory-of-polar-bears)
Grizzly Bears are Intruding into the Territory of Polar Bears - sanjay - 06-26-2015
Wapusk National Park is located at western side of the Hudson Bay near Churchill, Manitoba. This place is popular for polar bear population and it is one of the largest known polar bear maternity denning areas in the world.
Until now grizzly and black bears never have been reported at Wapusk National Park.
Researchers from the University of Saskatchewan set up a camera in the park that captured all three species of bear. Cameras have captured pictures of more than 200 polar and grizzly bears on 3 occasions. The cameras, triggered by motion and heat, have also captured the park's other animals, including wolves, caribou, moose, wolverines and geese.
Researcher Doug Clark tweeted out photos of the three bears, last weak. Photos that researcher Doug Clark tweeted out Thursday show grizzlies, polar bears and black bears in the vicinity of one camera mounted on a fence post in the park, roughly 100 kilometres southeast of Churchill, Man., within seven months of each other.
Clark told CBC News, "Seeing all three species of bear in Canada and in North America, at one spot, 'unique' doesn't even begin to describe it. There are only a couple of places where you'd even have the potential for that in North America and Wapusk National Park is the only place where that amount of overlap has been documented."
Clark, an assistant professor from the University of Saskatchewan, said that his research in conjunction with Parks Canada, began in 2011 as a fact-finding mission to determine how bears, polar bears specifically, operated around the national park's fenced-in research camps.
Why are grizzly bears suddenly showing up in polar bear habitat? Changes in climate could be part of the answer, especially as they move increasingly northward. Churchill represents an interesting intersection of the three species: far south for polar bears, normal for black bears, and actually a bit south for barren ground grizzly which are known to occur northwest of the Western Hudson Bay region.
Wapusk National Park sits on the edge of a transition zone between tundra and boreal forest. It’s also near the transition from polar bear territory to black bear territory. Seeing more grizzlies where they historically have not been seen could be due in part to changing habitat as a result of climate change.
Polar Bears International Senior Director of Conservation Geoff York said, "While black bears have been seen around Churchill for a very long time, grizzly bears appear to be newcomers to this region. The extent of their presence, the drivers behind their dispersion, and the potential impacts of their occurrence here remain as of yet unknown"
For decades, the story of grizzlies in North America has been one of decline but this might be a turn around for the species.
These cameras also allow Clark to analyze the original subjects of the research, polar bears. The pictures allow him to look at the mammals' body condition, their numbers and when they are appearing compared with the years prior.
According to Clark - Body condition is]a very important measure because with concern about polar bears losing access to seal hunting habitat due to climate warming and loss of sea ice, being able to monitor body condition is increasingly important.
The data from this spring is of the most interest to Clark because from 2011-14 Hudson Bay's ice broke up in relatively consistent time periods. This spring, there was a significantly earlier ice melt which will change the bears' behaviours. Clark is interested to see how.
Wapusk National Park is the only place where you can study human-bear interactions safely, thanks to the fenced research camps set up in the park, Clark said.
The location of the park is also key, Clark said, because it is nestled at the edge of the forest and tundra ecosystems, on the coast of Hudson Bay.
"Ecologically things are changing very, very rapidly and grizzlies moving in are just one of the more visible signs of it," Clark said.
The data collected this spring also showed robins in the area for the first time since they began their research.
"Being able to observe changes right at the edges of two habitats, where things are going to start to move, they're going to be the most apparent and the most visible and probably the most dramatic. So it's a wonderful place to ask questions about change too."
Below is image of same place from camera and you can see Polar, Grizzly and Black bear also Note the timing on photo
Polar Bear
*This image is copyright of its original author
Black Bear
*This image is copyright of its original author
Grizzly bears
*This image is copyright of its original author
*This image is copyright of its original author
*This image is copyright of its original author
*This image is copyright of its original author
actually it gets even more diverse: brown-phase black bear in Wapusk National Park
*This image is copyright of its original author
RE: Grizzly Bears are Intruding into the Territory of Polar Bears - Pckts - 06-26-2015
I wonder why black bears have been seen in the area for a long time but grizzlies are just now showing up?
Im sure it will happen more and more as the world changes and ice melts.
RE: Grizzly Bears are Intruding into the Territory of Polar Bears - sanjay - 07-25-2015
Following a post of great scientist and polar bear expert Dr. Thea Bechshoft on FB, She answered an interesting question asked by Jan on Polar and Grizzly bear interaction. I am re publishing it here for bear lovers
Question from Jan: "Is climate change affecting how polar bears and other bears interact? Are they coming into contact more often?"
Answer by Dr. Thea Bechshoft: The consequences of climate change are many and highly diverse. And yes, Jan - one of these changes do indeed concern a change in the interactions between polar bears and other bear species. As the temperatures are warming, grizzly bears (also known as brown bears) have started moving further north into what is otherwise considered polar bear territory. However, although polar bears and grizzlies are each other’s closest relatives, their biology is sufficiently different that they only meet under relatively specific circumstances.
Polar bears are specialized to living on the sea ice and hunting seals. When/if they are forced to stay on land they are basically starving while waiting for the sea ice to re-form. Grizzlies, on the other hand, are specialized to living on land, eating a largely vegetarian diet (an hibernating during the winter months).
During spring or summer, however, the two bear species may meet where land meets ocean, e.g. scavenging for anything edible that may have washed up along the shore. Every now and then these encounters will be romantic in nature, resulting in what is known as "grolar" or "pizzly" polar bear/grizzly hybrid cubs. Based on what has been observed in the field so far such cubs generally seem to have a polar bear mother and a grizzly father.
This means that the cubs will be raised as polar bears, and thus be highly likely to mate with a polar bear once they themselves reach reproductive age. In other words - under the current climate - the grizzly DNA will (over generations) disappear from the bloodline.
A few stories have been in the news lately on how the interactions between the bears (in Canada) are changing: http://bit.ly/1IoTOEP and http://bit.ly/1RDdI3V
PS: If you go online to look at pictures of polar bear/grizzly bear hybrids, remember that grizzly bears can be any color between dark brown and light beige, a fact which seems to have confused quite a few of those who’ve posted pictures on various websites! For one example of how a grolar may actually look, see here: http://bit.ly/1g94GR0.
RE: Grizzly Bears are Intruding into the Territory of Polar Bears - brotherbear - 01-03-2016
I believe that a grolar bear might have a difficult time and probably most of them die at a young age. Imagine the difficulty if his claws are not as deeply curved and he is unable to hook into the flesh of a seal or walrus. Although all bears seem to be good swimmers, the grolar bear is likely to be less adapted than a full-blooded polar bear. He might even have difficulty in climbing onto a big chunk of ice. Probably few live long enough to pass on their genes.
RE: Grizzly Bears are Intruding into the Territory of Polar Bears - brotherbear - 01-12-2016
http://www.nwf.org/News-and-Magazines/National-Wildlife/Animals/Archives/2006/Grizzly-Bears-on-Ice.aspx
Aklak vs. Nanook: A Tale of Two Bears
Like most scientists, the Inuit view Aklak, the grizzly bear, and Nanook, the polar bear, as two very different creatures. Their traditional tales of polar bears almost always portray these animals as powerful, keen-witted and worthy of great esteem. The grizzly, on the other hand, is seen as a more sinister beast, one that is likely to charge unexpectedly in an explosive manner.
Some biologists might agree with that assessment, citing evidence that barren ground grizzlies appear to be more aggressive than grizzlies living farther south. One explanation, they say, could be that northern grizzlies evolved in a treeless world where there's no place to hide, so threatening one's opponent may make far more sense than fleeing.
Whatever the reason, bear biologist Andrew Derocher says he is "a lot more comfortable capturing a big polar bear on the sea ice than a small grizzly on land. Grizzlies tend to react much more aggressively. It can be very unnerving."
RE: Grizzly Bears are Intruding into the Territory of Polar Bears - brotherbear - 01-12-2016
http://www.nwf.org/News-and-Magazines/National-Wildlife/Animals/Archives/2006/Grizzly-Bears-on-Ice.aspx
ABOUT 50 MILES NORTH of tree line in Canada's western Arctic, Andrew Derocher picked up the tracks of four grizzly bears following a herd of caribou across hard snow and ice toward the coast. Derocher, a University of Alberta biologist, wasn't sure whether the tracks had been left by a family or by a male following a female with two cubs. If it turned out to be the latter, he said, the mother and offspring could be in trouble. Contrary to what may appear in popular movies and books, a lone male grizzly is more likely to kill and eat bear cubs than befriend them.
By the time Derocher caught up with the bears, it looked like his fears were justified. With two cubs following close behind, the mother was loping off as fast as she could. Suddenly, she whirled around to confront her pursuer. But instead of beginning a bloody brawl, the bears stopped inches short of one another with no sign of aggression. "These four animals are together," concluded Derocher. "The female just turned around to check on her largest cub."
Known as "barren ground grizzlies," the bears Derocher observed are the same species of grizzly that inhabits the Rockies in southern Canada, the interior and coastal regions of British Columbia and Alaska and, in the Lower 48, Montana, Wyoming, northern Idaho and the North Cascades of Washington. Here, at the northern edge of the species' range--where the bears roam from the North Slope of Alaska to the coast of Canada's Hudson Bay--grizzlies look almost identical to their southern kin, but are only about two-thirds their size.
Barren ground grizzlies are among the most enigmatic of Arctic mammals. Few in number and rarely seen, they are as much myth as reality. Discovering how the bears manage to make a living in a treeless landscape that is covered in snow and ice for as long as nine months a year is one of the objects of Derocher's studies. But what really intrigues him are reports of more and more grizzlies showing up on sea ice, territory traditionally dominated by polar bears.
Researchers know that barren ground grizzlies feed on alpine hedysarum in spring, horsetail and bearflower in summer and berries in fall. They also dig up Arctic ground squirrels and other small mammals. Caribou, however, may be the most important compensation for the constraints these animals face. Biologists have found that the more a bear population feeds on caribou or other meat, the higher its densities are likely to be and the more successful an individual bear will be at reproducing.
It's not surprising, then, that in the absence of caribou in early springtime--when the animals emerge from their dens to find only snow and cold--barren ground grizzlies will occasionally venture onto the sea ice. The scent of a seal, dead or alive, or the tracks of a caribou herd that has crossed to an Arctic island may be all that's required for them to take that first step away from land.
But sightings of grizzlies on ice have increased since 1991, the year that Northwest Territories polar bear biologist Mitch Taylor first spotted one of the bears during a flight across Melville Sound, 600 miles north of mainland Canada. Researchers also have observed more than a dozen bears on Banks and Victoria Islands, 100 or more miles north of the mainland, and at least one has been spotted on Hudson Bay, where it appeared to be searching for seals.
The most startling discovery so far came in 2003, when Canadian glaciologist John England spied a grizzly along a river valley on uninhabited Melville Island. Not only was the bear more than 700 miles north of where scientists would have expected it to be, it was roly-poly and in as good a shape as a healthy grizzly could be.
England, who had worked 40 years in the Arctic, was flabbergasted by what he saw that day. The following year, researchers found fresh tracks and hair in the same area. DNA analysis of the hair samples showed that the bear had come from a population along the central Arctic coast of Canada more than 600 miles away. "The clear implication was that this grizzly had denned somewhere up around Melville, far from where grizzly bears are normally found," says England. "Presumably, it was feeding on muskoxen because apart from the occasional caribou you see high up on the Arctic islands there isn't much else for them to eat."
What grizzlies are actually doing up there in the kingdom of their great white cousins is not clearly understood. Biologists have long considered the differences between the two bears significant enough to warrant separate species status. Physical distinctions are obvious: Polar bears are white rather than brown, which helps camouflage the predators from their prey on the sea ice. They are also generally larger, and have heads and bodies that are much more elongated, and therefore better adapted to penetrate seal lairs. Their larger, sharper teeth allow them to tear up seals efficiently, and shorter claws and larger feet make it easier for polar bears to travel on sea ice and swim across great expanses of water.
Many Eskimos believe that rising temperatures in the Arctic explain why grizzly bears--as well as marten, wolverines and several other species of birds and mammals--are showing up in extreme northern places where they were rarely, if ever, seen before. Global warming, they say, is creating conditions that are more favorable for these animals, at least in the short term.
While most scientists see that idea as a genuine possibility, experts like Canadian Wildlife Service biologist Ian Stirling, who has studied polar bears for more than 30 years, suspects that some grizzlies have always been venturing onto the ice. Perhaps, Stirling says, "what we're witnessing today is behavior similar to the evolutionary process that resulted in polar bears filling a rich but vacant niche as supreme predator of the sea ice."
Like all creatures, barren ground grizzlies will continue to adapt and evolve. But just how successful they will be is unclear. Warmer temperatures that are already melting Arctic sea ice are also hitting caribou hard in places like the northern Yukon and Alaska, where the Porcupine caribou herd has dropped from an estimated 178,000 in 1989 to 123,000 today. The theory is that warmer spring days followed by cold snaps are making it harder for caribou to crater through the hard snow. Desperate for food, the animals are driven into windswept hills where they are more vulnerable to wolves, bears and the debilitating effects of malnutrition.
If caribou populations shrink dramatically, Derocher doesn't see much of a future for grizzlies in the Arctic. Nor does he see the bears moving north if a warming climate is going to melt sea ice. Another predicted consequence of climate change--northern migration of the tree line--may also hurt grizzlies; research has shown that the bears survive better in the barrens than they do in boreal forest.
What worries Derocher even more, though, are massive oil, gas and pipeline developments planned for Alaska and northern Canada. While the United States considers development in Alaska's Arctic National Wildlife Refuge, the Canadian government is fast-tracking a $5-billion natural gas pipeline down the Mackenzie Valley from the Beaufort Sea.
"This is a population at the edge," says Derocher. "They're at the edge of their northern range. They're smaller and they're resource poor. They have to work a lot harder to make a living up here." Add a pipeline, oil and gas wells and a road to their habitat, he says, "and it becomes pretty apparent that these animals are going to be challenged."
For now, though, the Arctic remains one of the last strongholds for grizzlies in North America. Farther south, many populations are struggling with industrial development and other human activity. During last year's field season, Derocher was heartened by the sight of the four grizzlies he had observed the year before. Somehow, in a wilderness that is frozen over for three-quarters of the year, this large family had found a way to make it through another winter.
Aklak vs. Nanook: A Tale of Two Bears
Like most scientists, the Inuit view Aklak, the grizzly bear, and Nanook, the polar bear, as two very different creatures. Their traditional tales of polar bears almost always portray these animals as powerful, keen-witted and worthy of great esteem. The grizzly, on the other hand, is seen as a more sinister beast, one that is likely to charge unexpectedly in an explosive manner.
Some biologists might agree with that assessment, citing evidence that barren ground grizzlies appear to be more aggressive than grizzlies living farther south. One explanation, they say, could be that northern grizzlies evolved in a treeless world where there's no place to hide, so threatening one's opponent may make far more sense than fleeing.
Whatever the reason, bear biologist Andrew Derocher says he is "a lot more comfortable capturing a big polar bear on the sea ice than a small grizzly on land. Grizzlies tend to react much more aggressively. It can be very unnerving."
NWF Priority: Guarding Grizzlies
For several years, NWF and its affiliates have been working to bring back the grizzly bear to areas in Western states where the species' populations plummeted beginning in the 1800s. In the Yellowstone Ecosystem, such actions--which include habitat restoration and reducing conflicts with ranchers--have been so successful that the species may soon be removed from the federal Endangered Species List. More recently, NWF has been combating global warming, which poses a special threat to Arctic ecosystems and their inhabitants, including the barren ground grizzly. To learn more, go to www.nwf.org/globalwarming.
Polar Bear Meltdown
As global warming causes Arctic sea ice to melt earlier each year, barren ground grizzlies and polar bears may come in contact more often if the great white bears are unable to reach their traditional prey--seals, which they hunt from ice floes--and are forced to go after land animals like caribou, a favorite fare of grizzly bears. If the two species must compete for prey, grizzlies are likely to prevail because they are the more aggressive of the two bears.
Already, there is evidence that polar bears are suffering as a result of global warming: Along the western shore of Canada's Hudson Bay, biologists have found that the bears weigh less and give birth to fewer cubs than they did two decades ago, when the ice was melting two weeks later than it does today.
The most recent, and dramatic, bad news about the bears emerged last December, when researchers discovered some 40 polar bears swimming as far as 60 miles off the northern coast of Alaska. At least 4 of the animals drowned. While polar bears can swim short distances between ice floes, disappearing ice may increasingly force them to swim longer distances, making it more likely that the bears will tire and drown.--Laura Tangley
RE: Grizzly Bears are Intruding into the Territory of Polar Bears - GreenGrolar - 04-16-2022
RE: Grizzly Bears are Intruding into the Territory of Polar Bears - GreenGrolar - 01-17-2023
Here we have the first documented case of an adult male polar bear successfully defending his kill from a grizzly bear:
*This image is copyright of its original author
A polar bear successfully defending a marine mammal carcass from an approaching grizzly bear, Kiask Island, 2013 (photo: Robert Rockwell).
Two observations were of grizzly bears feeding on subadult polar bears but in those cases neither observer could conclusively determine whether the grizzly bears had killed them, though the details of one case strongly suggested so. Grizzly bears are known to have killed and consumed polar bears on the sea ice in the western Arctic (Taylor, 1995) and typically dominate polar bears when they interact on shore in Alaska (Miller et al., 2015). These two observations contrast though with Rockwell’s 2013 observation of an adult male polar bear successfully deterring an approaching grizzly that appeared attracted to an unidentiable marine mammal carcass the polar bear was standing on (Fig. 2f).
The State of Knowledge about Grizzly Bears (Kakenokuskwe osow Muskwa (Cree), Ursus arctos) in Northern Manitoba
https://www.researchgate.net/publication/359235217_The_State_of_Knowledge_about_Grizzly_Bears_Kakenokuskwe_osow_Muskwa_Cree_Ursus_arctos_in_Northern_Manitoba
This is probably what happens when a polar bear loses its fear of the barren ground grizzly.