Telegraph: The polar bears of Hudson Bay, Canada migrate onto land in the summer when the sea ice melts, relying on fat reserves to survive until the sea re-freezes in late November or early December.
During the winter and spring months they use the sea ice to hunt their prey of seals.
But the bears were coming to land earlier and leaving later in recent years as a result of climate change which was reducing the ice, researchers writing in the Journal of Animal Ecology from the British Ecological Society...