Between 2012 and 2014 another six hybrid bears were either killed by hunters or live-captured by biologists. Samples were collected from all six, and genetic analysis confirmed both their hybrid status and their family relationships. [1] The eight hybrids identified to date include four first-generation ( F1, 50:50) and four grizzly bear backcross individuals (75:25 grizzly:polar bear). A single F1 female was the mother of all four backcross individuals, and a single female polar bear was the mother of all four F1s, and thus the grandmother of all four backcross bears. Two male grizzlies mated with the female polar bear to give rise to the four F1s, with one grizzly bear apparently mating with the polar bear in two different years (two of the F1s are full siblings, but born three years apart). The same two male brown bears both mated with the F1 female to produce the four backcross individuals, with three littermates being sired by one male and a single, older 3/4 grizzly bear coming from a mating between the F1 female and her father.
Adding after this↑
We do not have an exact reason this is happening. One theory is with the grizzly population increasing male bears will leave their dens sooner while females stay with their cubs. This means that to the male grizzles, female polar bears have become viable mates. This is the reason that hybrids, that are born from one polar bear and one grizzly bear, have been reported to have grizzly fathers and polar mothers. Scientists have hypothesized this may be a climate change issue. As winters begin to get shorter grizzlies begin to move more highly expanding their territory. This expansion in territory has seen an expansion in what these grizzles are eating. With the lack of berries in the artic grizzlies have been seen hunting seals, which is a common prey for polar bears. This could be another reason for the hybrid as they are so close while hunting. [2]
It is currently unknown why grizzly bears are being found in the habitat of polar bears. [3]Although a grizzly bear was killed on Banks Island in 1951, it has until recently been rare for this species to stray far north of the coast of mainland Canada. In 1991 one or more grizzly bears were documented hunting seals and polar bears on the sea ice near Melville Island, over 500 km from the mainland coast.[18] In 2003 and 2004 a geological team working on Melville Island obtained photographic and DNA evidence of a grizzly bear in the area.[19] Their report also collated information on several other sightings in the Canadian Arctic Archipelago.
- ^ Richardson, Evan; Branigan, Marsha; Paetkau, David; Pongracz, Jodie D. (May 31, 2017). "Recent Hybridization between a Polar Bear and Grizzly Bears in the Canadian Arctic". Arctic. 70 (2): 151–160. doi: 10.14430/arctic4643.
- ^ Struzik, Ed (December 2006). "Pizzlies of the Arctic". Canadian Geographic. 126 (6): 41 – via Academic Search Premier.
- ^ Struzik, Ed (December 2003). "Grizzlies on Ice". Canadian Geographic. 123 (6): 38 – via Academic Search Premier.
Between 2012 and 2014 another six hybrid bears were either killed by hunters or live-captured by biologists. Samples were collected from all six, and genetic analysis confirmed both their hybrid status and their family relationships. [1] The eight hybrids identified to date include four first-generation ( F1, 50:50) and four grizzly bear backcross individuals (75:25 grizzly:polar bear). A single F1 female was the mother of all four backcross individuals, and a single female polar bear was the mother of all four F1s, and thus the grandmother of all four backcross bears. Two male grizzlies mated with the female polar bear to give rise to the four F1s, with one grizzly bear apparently mating with the polar bear in two different years (two of the F1s are full siblings, but born three years apart). The same two male brown bears both mated with the F1 female to produce the four backcross individuals, with three littermates being sired by one male and a single, older 3/4 grizzly bear coming from a mating between the F1 female and her father.
Adding after this↑
We do not have an exact reason this is happening. One theory is with the grizzly population increasing male bears will leave their dens sooner while females stay with their cubs. This means that to the male grizzles, female polar bears have become viable mates. This is the reason that hybrids, that are born from one polar bear and one grizzly bear, have been reported to have grizzly fathers and polar mothers. Scientists have hypothesized this may be a climate change issue. As winters begin to get shorter grizzlies begin to move more highly expanding their territory. This expansion in territory has seen an expansion in what these grizzles are eating. With the lack of berries in the artic grizzlies have been seen hunting seals, which is a common prey for polar bears. This could be another reason for the hybrid as they are so close while hunting. [2]
It is currently unknown why grizzly bears are being found in the habitat of polar bears. [3]Although a grizzly bear was killed on Banks Island in 1951, it has until recently been rare for this species to stray far north of the coast of mainland Canada. In 1991 one or more grizzly bears were documented hunting seals and polar bears on the sea ice near Melville Island, over 500 km from the mainland coast.[18] In 2003 and 2004 a geological team working on Melville Island obtained photographic and DNA evidence of a grizzly bear in the area.[19] Their report also collated information on several other sightings in the Canadian Arctic Archipelago.
- ^ Richardson, Evan; Branigan, Marsha; Paetkau, David; Pongracz, Jodie D. (May 31, 2017). "Recent Hybridization between a Polar Bear and Grizzly Bears in the Canadian Arctic". Arctic. 70 (2): 151–160. doi: 10.14430/arctic4643.
- ^ Struzik, Ed (December 2006). "Pizzlies of the Arctic". Canadian Geographic. 126 (6): 41 – via Academic Search Premier.
- ^ Struzik, Ed (December 2003). "Grizzlies on Ice". Canadian Geographic. 123 (6): 38 – via Academic Search Premier.