Grizzly-polar bear hybrid

A grizzly-polar bear hybrid is a rare ursid hybrid that has occurred both in captivity and in the wild. In 2006, the occurrence of this hybrid in nature was confirmed by testing the DNA of a strange-looking bear that had been shot by an American sport hunter. Previously, the hybrid had been produced in zoos and was considered a "cryptid" (a hypothesized animal for which there is no proof of existence in the wild).

Biology

The grizzly bear and polar bear are sufficiently genetically similar that they can interbreed and produce fertile offspring. By the strict interpretation of the biological species concept, this would imply that brown bears and polar bears are variants of the same species; however, interbreeding is so rare, that only a minimal amount of genetic material is exchanged between the two species. This severe reduction in gene flow is sufficient to treat them as two different species under the normal use of the biological species concept. A similar situation occurs with the red wolf and coyote where hybridization occurs in the wild without evidence of hybrid breakdown.

A number of polar bear hybrids are described as Ursid hybrid, a term that designates any hybrid of two species within the Ursidae family. Polar bear hybrids with Kodiak bears have been reported and shot, but DNA techniques were not available to verify the bears' ancestry.

Occurrences in the wild

With one confirmed case and other suspected sightings, zoologists are theorizing how wild hybrids might come into being. Although the two animals are genetically similar and often are 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 stay — and breed — on land. Polar bears prefer the water and ice, and breed on the ice. The two species have been observed feeding together on whale carcasses, although they have never actually been seen mating in the wild.

Possible early sightings

Clinton Hart Merriam, taxonomist of grizzly bears, described an animal killed in 1864 at Rendezvous Lake, Northwest Territories, Canada as "buffy whitish" with a golden brown muzzle. This is considered to be a natural hybrid between a grizzly bear and polar bear. A similar bear was reported from Kodiak Island. In 1943, Clara Helgason described a bear shot by hunters during her childhood. This was a large, off-white bear with hair all over his paws. The presence of hair on the bottom of the feet suggests it was not an unusually colored Kodiak brown bear, but a natural hybrid with a polar bear. Brown bears vary considerably in color from cream to almost black,Grizzly Bear so additional evidence beyond the coat color (e.g. hair on the soles, general morphology) is needed before an inference of hybridisation can be made for unusually coloured bears.

2006 discovery

Jim Martell, a hunter from the United States, found and shot a grizzly-polar bear hybrid near Sachs Harbour on Banks Island, Northwest Territories, Canada, reportedly on April 16, 2006. Martell had been hunting for polar bears with an official license, and killed the animal believing it to be a normal polar bear. Officials took interest in the creature after noticing that 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, he would have faced a possible dollar|CAN$" target="_blank" >^*1000 fine and up to a year in jail.

A DNA test conducted by Wildlife Genetics International in British Columbia confirmed that it was a hybrid, with the mother a polar bear and the father a grizzly. It is the first documented case in the wild, though it was known that this hybrid was biologically possible and other ursid hybrids have been bred in zoos in the past.

The carcass will be returned to Martell, who told the National Post, "It will be quite a trophy."

Naming

Since the 2006 discovery placed the hybrid into the spotlight, the media have referred to this animal with several portmanteau names, such as pizzly, grolar bear,"Hunter may have shot grolar bear – or was it pizzly?", CBC North, 26 April 2006. and polizzly; but there is no consensus on the use of any one of these terms. Canadian wildlife officials have suggested calling the hybrid "Nanulak," taken from the Inuit names for polar bear (Nanuk) and grizzly bear (Aklak)."Hybrid bear shot dead in Canada," BBC Science, 13 May 2006 By one conventionNaming Conventions A semi-scientific reference for hybrid naming conventions, with specific examples of big-cat hybrids. the name of the sire comes first in such combinations: the offspring of a male Polar bear and a female Grizzly would be a "Pizzly bear," while the offspring of a male Grizzly and a female Polar bear would be a "Grolar bear."

References

External links

CBC Article
CBC News Story
Wild find: Half grizzly, half polar bear - Msn.com
Hybrid mammals - bears (subsection)
The North This Week (MP3) (CBC podcast including interviews with scientist Ian Stirling, guide Roger Kuptana, and hunter Jim Martell)

2006 in Canada | Bears | Mammal hybrids | Northwest Territories

Hibrida grizzly-beruang kutub | Griza-polara hibrida urso | 灰北極熊