It’s a Grolar, the climate–change polar bear. By Rachel Fritzman

Polar bears and Grizzlies For the first time, grizzly bears and polar bears are mating with each other in the wild.

Discovered This was first discovered in 2006 when a hunter shot what he thought was a polar bear. After genetic testing it was discovered that it was a hybrid of a grizzly bear father and a polar bear mother.

Why is this happening? Grizzly Bears are traditionally found in Alaska, western Canada, and northwestern America. More and more, Grizzlies are being spotted in eastern Canada which was previously dominated by polar bears, and hundreds of miles north on Canadian Arctic islands.

Why is this happening? The loss of habitat for polar bears is also driving them to land, where they may come into contact with grizzlies. Due to global warming, as Arctic sea ice melts, closely related species in the North Pacific and North Atlantic are able to come into contact with each other and as a result they can interbreed.

How is this possible? When bears come into contact with each other, they usually tend to act very aggressive towards each other. Even bears of the same species will often view each other as prey.

How is this possible? However, these rules change during mating season. Grizzly bears mate from May to July Polar Bears mate from April to June Because they are now coming in contact and their mating seasons overlap, this makes it possible.

How is this possible? Both species require an extended mating ritual in order to reproduce. Females are only able to ovulate after spending several days with a male. During this time, they mate several times over several days to ensure fertilization.

So this is no accident

Similarities Polar bears are believed to have evolved from grizzly bears during the ice age when they were cut off in an area of Alaska. As a result their DNA is very similar. This allows their offspring to be fertile.

Characteristics of offspring Longer necks found on polar bears. Shoulder hump found on grizzly bears. Soles of feet partially covered in hair. White fur with brown patches

Is this happening with other arctic species?....YES Hybridization has already happened between harp and hooded seals, narwhal and beluga whales, and is very likely between North Pacific right whales and bowhead whales.

Consequences of invasion There are at least 22 Arctic marine mammals are at risk from hybridization. Many of these animals are already threatened or endangered without this risk.

Consequences of invasion Because of hybridization and invasion of species, some southern marine mammals are also bringing diseases that Arctic marine mammals have no immunity to. This possibility was realized when a parasitic roundworm, found in polar bears and arctic fox, began to spread to walrus and then to humans who had eaten uncooked the walrus meat.

Consequences of invasion Another disease being spread due to this is brucellosis, a bacterial disease found in cattle, dogs, wild animals and humans, which has been linked to reproductive failure in dolphins and baleen whales.

Consequences of invasion The greatest life threatening disease that could spread to the arctic is phocine distemper. This disease was first found in 1988 when it killed 20,000 harbor seals in northwestern Europe. Since then it has spread to seals in Russia, striped dolphin in the Mediterranean and other marine mammals around the world.

Consequences of invasion No one is sure how this disease was introduced to marine life, but it is closely related to canine distemper so it is believed the the remains of an infected animal were dumped into the ocean.

Consequences of invasion Narwhals and beluga whales have no immunity to this disease, so if it gets introduced to the North American Arctic, with 80,000 narwhal and 150,000 belugas most of the year, there would be a massive die off that would be incredibly destructive to the arctic community.

Stopping invasion and interbreeding Global warming has hit the Arctic region two to three times harder than it has hit other areas of this climate. Because of this, polar bears, along with other arctic species are being forced out of their normal hunting grounds. The only thing that we can do to slow the disappearance of ice caps is drastically reduce our carbon dioxide emissions.

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