Grizzly–polar bear hybrid
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Ursid hybrids, a term that designates any hybrid of two species within the family Ursidae, include several other types of polar bear hybrids. Polar bear hybrids with grizzly bears in the wild have been reported and shot in the past as well, but DNA techniques were not available to verify the bears' ancestry.
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[edit] Occurrences in the wild
With three confirmed cases and other suspected sightings,[4] zoologists are hypothesizing how wild hybrids might come into being. Although the two species are genetically similar and often found in the same territories, they tend to avoid each other in the wild. They also fill different ecological niches. Grizzlies (and also Kodiak bears and "Alaskan brown bears", which are all subspecies of the brown bear, Ursus arctos), tend to live and breed on land. Polar bears prefer the water and ice, usually breeding on the ice. The yellowish-white MacFarlane's bear, a mysterious animal known only from one specimen acquired in 1864, seems to attest that grizzly-polar bear hybrids may have always occurred from time to time. Another theory suggests that the polar bears have been driven southward by the melting of the ice cap, bringing them into closer contact with grizzly bears.[edit] 2006 Discovery
Jim Martell, a hunter from Idaho, found and shot a grizzly–polar bear hybrid near Sachs Harbour on Banks Island, Northwest Territories, Canada, reportedly on 16 April 2006.[1][3] Martell had been hunting for polar bears with an official license and a guide, at a cost of $45,450,[5] and killed the animal believing it to be a normal polar bear. Officials took interest in the creature after noticing it had thick, creamy white fur, typical of polar bears, as well as long claws; a humped back; a shallow face; and brown patches around its eyes, nose, and back, and having patches on one foot, which are all traits of grizzly bears. If the bear had been adjudicated to be a grizzly, the hunter would have faced a possible CAN$1,000 fine and up to a year in jail.[6]A DNA test conducted by the Wildlife Genetics International in British Columbia confirmed it was a hybrid, with the mother a polar bear and the father a grizzly.[3] It is the first documented case in the wild,[7] though it was known that this hybrid was biologically possible and other ursid hybrids have been bred in zoos in the past.
Amidst much controversy, the bear has since been returned to Martell.[8][9]
[edit] 2010 Discovery
On 8 April 2010, David Kuptana, an Inuvialuit hunter from the nearby community of Ulukhaktok on Victoria Island shot what he thought was a polar bear. After inspecting the bear and having DNA testing done, it was found that the bear's mother was a grizzly-polar hybrid and the father was a grizzly bear. The Department of Environment and Natural Resources for the NWT said that it "...may be the first recorded second-generation polar-grizzly bear hybrid found in the wild."[10] The bear possesses physical characteristics intermediate between grizzlies and polar bears, such as brown fur on its paws, long claws and a grizzly-like head.[edit] 2010 Report
Biologists affiliated with the American Museum of Natural History and City College of the City University of New York have prepared a new report published in Canadian Field Naturalist that offers the first documented evidence that grizzlies are migrating into polar bear territory. Researchers found that seven grizzlies had been spotted in Wapusk National Park south of Churchill, Manitoba, between 2003 and 2008.[11][12][edit] Naming
[edit] Characteristics
Two grizzly–polar bear hybrids were born at Osnabrück Zoo, Osnabrück, Germany, in 2004 (one female and one male), and their physical traits are generally an intermediate between the polar bear and the grizzly bear.[16] For example, their bodies are smaller than polar bears, but larger than grizzlies, while their heads fall between the broader grizzly head and the leaner polar bear head.[16] They have long necks like polar bears, but small shoulder humps like grizzlies.[16] The soles of the hybrids' feet are partially covered in hair; polar bears have hair-covered soles, which act as insulation, and grizzlies have hairless soles.[16] Similarly, the hair of the hybrids exhibits a pattern of hollowness, which blends the traits of both polar bears and grizzlies. In cross section, the hair of polar bears is hollow, while the hair of grizzlies is either solid or has small hollow regions.[16] This varies according to which part of the grizzly the hair is located.[16] In the hybrid male, the paw hair was solid, but the dark back hair was somewhat hollow, albeit with "smaller empty regions than found in polar bear hair".[16] The hair of the female hybrid, "contains a range of hollow regions".[16]The hybrids demonstrated behavior more similar to polar bears than grizzlies. They stamped toys similar to how polar bears break ice, and hurled bags to the side "as polar bears may hurl prey".[16] Grizzlies given the same bags do not demonstrate this hurling behavior.[16] The hybrids were also observed lying down similar to polar bears: on their stomachs with rear legs splayed.[16]
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