Hungry polar bears are now resorting to cannibalism as a result of global warming, according to a report published in the journal Arctic.

The gruesome behavior was initially observed by environmental photojournalist Jenny Ross in Olgastretet, a passage of water that divides Norway's Svalbard archipelago.

Ross captured the shocking images which depict an adult polar bear dragging the body of a cub that it had killed. At first, the photojournalist thought the corpse was that of a seal, only realizing at a closer look that it was a young bear, the BBC reported.

At the 2011 American Geophysical Union Meeting in San Francisco, Ross described three instances of killings and cannibalism of polar bear cubs by adult males, a behavioral response to food scarcity.

Ross blamed the rapid decline in Arctic sea ice during the summer months for the appearance of cannibalism. Polar bears primarily hunt seals for food.

There are increasing numbers of observations of it occurring, particularly on land where polar bears are trapped ashore, completely food-deprived for extended periods of time due to the loss of sea ice as a result of climate change, Ross told the  BBC.

Ross co-authored a report with polar bear biologist Ian Stirling at the University of Alberta published in the December issue of the journal Arctic.

The photojournalist described what happened when her boat approached the adult bear that had preyed on the cub. As soon as the adult male became aware that a boat was approaching him, he basically stood to attention - he straddled the young bear's body, asserting control over it and conveying 'this is my food', she said in a report on BBC.

He then picked up the bear in his jaws and, just using the power of his jaws and his neck, transported it from one floe to another. And eventually, when he was a considerable distance away, he stopped and fed on the carcass.

Ross observed another polar bear nearby and believed it may have been the dead cub's mother.

This isn't the first time a polar bear was observed eating juvenile bears; there have been numerous related incidents in the recent past. In late 2009, cannibalism among polar bears was witnessed on the shores of Hudson Bay near the Canadian town of Churchill, Manitoba.