Conventional wisdom about polar bears is that they spend most of their time out hunting on the sea ice, except during the warm summer months when the sea ice recedes and the bears are forced to return to land as a final refuge. But a surprising new discovery by a group of filmmakers shooting on location in Greenland could challenge that idea, reports BBC Nature.
The filmmakers came across at least 20 polar bears living out the summer on a large tabular iceberg, called the Peterman Iceberg, in Baffin Bay, some 50 kilometers off the Canadian coast. This means that not all polar bears return to solid land when much of the ice melts. Large icebergs may therefore act as 'sanctuaries' for the bears, giving them someplace to hunker down and wait for the sea to freeze over again.
"What's there for them is security, and I think they are taking advantage of that," said Chris Packham, one of the filmmakers who made the discovery. "So I think they are living on this iceberg to stay safe, and just wait for the sea ice to come back in."
According to American polar bear expert Steven Amstrup, this is the first time a signifcant group of bears have ever been found eking out an existence on a large iceberg.
There are several explanations that could explain the new behavior, if in fact it is new. One theory is that the iceberg offers them safety from human hunters on land. Polar bears are hunted on both the mainlands of Greenland and Canada. Another possibility is that increased melting in the region is causing more large icebergs to become separated from the land, essentially 'stranding' the bears.
"In recent years we've been seeing a lot more big tabular icebergs come off the Greenland ice sheet and they're now ending up in Baffin Bay," said Dr. Keith Nicholls of the British Antarctic Survey, another member of the expedition.
By Bryan Nelson