Grizzly Bears are Intruding into the Territory of Polar Bears

[sanjay]

Following a post of great scientist and polar bear expert Dr. Thea Bechshoft on FB, She answered an interesting question asked by Jan on Polar and Grizzly bear interaction. I am re publishing it here for bear lovers

Question from Jan: "Is climate change affecting how polar bears and other bears interact? Are they coming into contact more often?"

Answer by Dr. Thea Bechshoft: The consequences of climate change are many and highly diverse. And yes, Jan - one of these changes do indeed concern a change in the interactions between polar bears and other bear species. As the temperatures are warming, grizzly bears (also known as brown bears) have started moving further north into what is otherwise considered polar bear territory. However, although polar bears and grizzlies are each other’s closest relatives, their biology is sufficiently different that they only meet under relatively specific circumstances.

Polar bears are specialized to living on the sea ice and hunting seals. When/if they are forced to stay on land they are basically starving while waiting for the sea ice to re-form. Grizzlies, on the other hand, are specialized to living on land, eating a largely vegetarian diet (an hibernating during the winter months).
During spring or summer, however, the two bear species may meet where land meets ocean, e.g. scavenging for anything edible that may have washed up along the shore. Every now and then these encounters will be romantic in nature, resulting in what is known as "grolar" or "pizzly" polar bear/grizzly hybrid cubs. Based on what has been observed in the field so far such cubs generally seem to have a polar bear mother and a grizzly father.
This means that the cubs will be raised as polar bears, and thus be highly likely to mate with a polar bear once they themselves reach reproductive age. In other words - under the current climate - the grizzly DNA will (over generations) disappear from the bloodline.

A few stories have been in the news lately on how the interactions between the bears (in Canada) are changing: http://bit.ly/1IoTOEP and http://bit.ly/1RDdI3V

PS: If you go online to look at pictures of polar bear/grizzly bear hybrids, remember that grizzly bears can be any color between dark brown and light beige, a fact which seems to have confused quite a few of those who’ve posted pictures on various websites! For one example of how a grolar may actually look, see here: http://bit.ly/1g94GR0. Reply