The US government says land that oil and gas companies want to drill in Alaska is a crucial home for polar bears.
Environmentalists hope this announcement will help save the endangered animals.
Right now in an icy den in the Arctic, a polar bear is giving birth to cubs, or is about to. But the very survival of this fearsome, majestic species concerns many humans.
Polar bears live and hunt on sea ice, but the frozen Arctic Ocean is melting at an increasing rate, a result, scientists say, of global warming caused by greenhouse gases.
Now the US government has designated nearly half a million square kilometres in Alaska as critical habitats for the polar bear. It covers an area of roughly twice the size of the United Kingdom, and it means any proposed economic activity there, must be weighed against its impact on the bears' habitat. It includes some of the Chukchi and Beaufort Seas, exactly where the oil company, Shell, wants to drill.
The designation itself doesn't ban oil exploration, but it adds extra hurdles that opponents say will harm the economy.
Environmentalists welcome the move, saying now they can write a recovery plan for polar bears, not an obituary.