Musk oxen, which were valued by the sailors on the whaling ships for their fresh meat and tradable fur, were wiped out in the Alaskan tundra and the northeastern coast of Greenland. Later, in the early 1900's when musk oxen calves became popular in zoos, the protective adult population was decimated in order to safely collect the calves. It was not until 1917 that Canada finally enacted laws to protect musk oxen. By then, only 500 remained living in the wild in the Canadian tundra and only several thousand in other arctic areas of the world.
The caribou were also an over hunted animal. By 1950, herds in North America were reduced by ninety percent.
Today, many countries have passed laws protecting animals from over hunting. In the arctic tundra animals, such as the caribou, musk oxen, arctic foxes, and polar bears, are protected by these laws. Because of these laws musk oxen numbers in Canada are now up to about 40,000. In Alaska there is a herd of about 1,000. Caribou numbers are also climbing, however they have not yet come close to their original numbers.
Although wildlife refuges and national parks in Alaska and Canada give animals added protection from hunting, their lives are also threatened by toxic pollutants. Pesticides can make its way through a food chain and kill whole families of animals. For example, if a peregrine falcon eats prey that has indirectly ingested pesticides , when the falcon lays its eggs they will crack before its young are ready to hatch. Indirect pesticide consumption is blamed for causing the peregrine falcon to become an endangered species.