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Coyotes-Wolves-Cougars.blogspot.com

Grizzly bears, black bears, wolves, coyotes, cougars/ mountain lions,bobcats, wolverines, lynx, foxes, fishers and martens are the suite of carnivores that originally inhabited North America after the Pleistocene extinctions. This site invites research, commentary, point/counterpoint on that suite of native animals (predator and prey) that inhabited The Americas circa 1500-at the initial point of European exploration and subsequent colonization. Landscape ecology, journal accounts of explorers and frontiersmen, genetic evaluations of museum animals, peer reviewed 20th and 21st century research on various aspects of our "Wild America" as well as subjective commentary from expert and layman alike. All of the above being revealed and discussed with the underlying goal of one day seeing our Continent rewilded.....Where big enough swaths of open space exist with connective corridors to other large forest, meadow, mountain, valley, prairie, desert and chaparral wildlands.....Thereby enabling all of our historic fauna, including man, to live in a sustainable and healthy environment. - Blogger Rick

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Friday, July 8, 2011

A theory has been put forth that the Irish Brown Bear(a forest dweller) and the Polar Bear interbred 120,000 years ago (during historic climate change) to create the modern Polar Bear that exists today...........Due to the climate change happening now, Polar Bears and Grizzly Bears are encountering each other, mating and producing hybrid offspring..........Might this be a way for the water loving Polar bear to adapt to land as the ice islands it depends on melt and disappear..........Will the hybrids be able to prey successfully on land dwelling prey whereas now, Polar Bears are inept hunters on land?

Ancient Irish roots discovered for modern polar bear


 Twisted lines of ancestry seem to have intertwined two very different species: the water-loving polar bear and the forest-loving Irish brown bear. Despite being so different, the two seem to have found love: Meeting and breeding at least once during the last 120,000 years, the two species gave rise to the polar bears we know today. "The Irish genetic sequences are much closer to the modern polar bear," said study researcher Daniel Bradley, of Trinity College Dublin. "As the climate has changed, what we are seeing is the tracking of that climatic change in the sequences in the bears."
The researchers started by analyzing the DNA of brown bears from Ireland and comparing it with that of ancient and modern polar bears. They used samples from bear skeletons found in Irish and British caves. The oldest skeletons were 120,000 years old and the youngest were at least 3,000 years old, the latter having died shortly before the bears went extinct in the area.  Comparing a special kind of genetic material -- called mitochondrial DNA -- of these bears, the researchers found the modern polar bear's DNA was very similar to that of the Irish brown bears. The bears seem to have intermixed their DNA in the last few dozen millennia, sometime between 20,000 and 50,000 years ago. "It's interesting because polar bears really are marine animals," Bradley said. "That's not the case for these brown bears."

Previous DNA evidence has linked polar bears to Alaskan brown bears originating in the ABC Islands (which consists of Admiralty, Baranof, and Chichagof) about 14,000 years ago. While both groups are brown bears, Bradley said that the Alaskan bear genetics doesn't match the polar bear as well as the Irish bears' does.

Earth's climate swung saw warmer and colder periods during the Irish bears' reign. As it changed, so did the bears' habitat. During cool times, the brown bears may have encountered polar bears on the ice that covered their normal habitat, while in warm times, the polar bears might have left their watery homes in search of food. 

 Our current climate is also showing evidence of polar-brown bear hybridization. Grizzly-polar (also called prizzly or grolar) bear hybrids are popping up in the Canadian arctic, and seem to be fertile, resulting in second-generation hybrids, a very unusual event for wild animals.  Hybridization might be what each species needs to survive changing climate, or it might result in a whole new species that fills a new ecological corner. Learning more about the genetic history of the polar bear, and about these brown-polar hybrids, could help inform conservation strategies for both, said study reasearcher Beth Shapiro, of Pennsylvania State University.

Lingering doubt

Charlotte Lindqvist, a researcher at the University of Buffalo in Buffalo, N.Y., who wasn't associated with the study, said she needs more data to come to the same conclusions as Bradley and Shapiro. She recommends sequencing longer sections of the mitochondrial DNA and taking a look at the nuclear DNA.  "Oftentimes...those relationships can change around as you go from mitochondrial data to nuclear data," Lindqvist told LiveScience. "That [additional data] could change the story around completely." Bradley agrees researchers need to take a closer look at the nuclear DNA.  "We haven't done that yet," he said, but added that he thinks the mitochondrial data is sound. "Before this data, the closest brown bear sequences were in Alaska, but our sequences were much closer."

The study was published  in the journal Current Biology.

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