The animals are irritated because they are ready to leave the area and start hunting in the deep sea, but ice is too thin, said Malakhova.

As Arctic sea ice melts, polar bears are spending more time near the Alaska North Slope village of Kaktovik. Now, federal prosecutors have charging a whaling captain there with killing one in violation of the Marine Mammal Protection Act.

Thinning sea ice has driven more than 50 polar bears ashore on an Arctic archipelago in northern Russia, causing chaos for the local population.