President Barack Obama surprised environmentalists and the fossil fuel industry alike when he announced a permanent, sweeping ban on oil drilling in much of the U.S. waters in the Arctic and Atlantic on Tuesday, in a decision that experts say would be difficult for a future administration to reverse.

The ban, which prevents offshore drilling from Virginia to New England and in much of the U.S. Arctic, joins an effort announced by Canada this week to prohibit oil exploration in northern Canadian waters as well. Given low prices for oil and the difficulty of deep water extraction, particularly in the frigid north, the industry hasn't exactly been chomping at the bit. But environmentalists have long warned about the future potential for drilling, as technology improves.

The ban will go a long way to protecting pristine beaches and water for people to enjoy, as well as serving as a boon to wildlife. Not only are animals threatened by oil spills and industrial activity, but by limiting exploration of fossil fuels Obama's action may help slow the release of greenhouse gases—which is driving climate-related threats to wildlife habitat.

Among the species that are most likely to benefit:

1. Polar Bears

Often seen as the symbol of the Arctic, polar bears are among the more embattled of well-known species on the planet. They depend on ice floes and clean water across large territories, to track and hunt their prey.

Polar bears are threatened both by melting ice, thanks to global warming, and pollution from oil drilling activities, which can poison their prey. (Read "On Thin Ice" in National Geographic magazine.)

2. Narwhals

Sometimes called the "unicorn of the sea," narwhals are porpoises found in Arctic coastal and river waters, but in decreasing numbers. The animals live in social groups and feast on shrimp, squid, and fish. Scientists aren't sure what the males' massive tusks are for—they can grow nearly nine feet long and are made of ivory—but suspect they may play a role in mating rituals.

Narwhals are considered at high risk from oil spills.

3. Walruses

Walruses Swarm Beaches as Ice Melts

Sometimes seen in massive "haul-outs" by the thousands, walruses are most often found near the Arctic Circle. The large marine mammals are extremely social and are distinguished by their long white tusks, grizzly whiskers, flat flippers, and bodies full of blubber.

The walrus was hunted nearly to extinction in historic times but has recovered some of its range. The animals are vulnerable to climate change, however, and scientists worry that oil spills could exacerbate the problem.

4. North Atlantic Cod

Once abundant, North Atlantic cod supported a robust fishing industry for generations, helping the economies of New England and eastern Canada get established. But overfishing has caused numbers of the fish to plunge, and populations have not recovered since crashing in the 1990s.

"The entire ecosystem seems to have changed," scientists said in a recent report, and "this may involve a climate influence due to changing ocean currents and the influx of cold Arctic waters." (Read more about overfishing's impact on New England cod.)

But prohibiting oil drilling in what remains of their habitat may help the species recover.

5. Cold and Deep-Water Corals

Although tropical reef corals are the best known, scientists are increasingly finding cold and deepwater corals of various species and hues. These sedentary animals are less known by science, but they are thought to play vital roles in their ecosystems.