Grizzly-Polar Bear Hybrid

The discovery:

Jim Martell, a hunter from the USA, found and shot a grizzly–polar bear hybrid near Sachs Harbour in Canada, reportedly on April 16,2006. Martell had been hunting for polar bears with an official license and a guide, at a cost of $50,000, 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 CAN$1,000 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 grizzly bear and polar bear are sufficiently similar genetically 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 wolfand coyotewhere hybridization occurs in the wild without evidence of hybrid breakdown.

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).
Other same kind of animals mules----( cross of female horse and a male donkey)., hinny (a cross between a female donkey and a male horse ),zeedonk (a zebra/donkey cross)

Theories of the Occurence:

With one confirmed case and other suspected sightings, zoologists are theorizing how wild hybrids might come into being. Although the two species 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. Some theories suggest that global warming has caused the ice to thin and caused the polar bears to be unable to hunt or "live" in their natural habitat. Because of this they have moved further inland, and it is believed that they began mating there in the wild, though they have never been seen doing this. Skeptics attempting to disprove the global warming theory of hybridization are quick to point to alleged sightings of this hybrid in 1864 prior to the onset of global warming.

Current State of Development :

The grizzly bear and polar bear are sufficiently similar genetically 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.