Arctic Alaska settlement in Arctic Alaska was driven first by discoveries of gold and later on by the extraction of petroleum. The ecosystem consists largely of tundra covering mountain ranges and coastal plains which are home to bears, wolves, sheep, oxen, reindeer, and numerous species of birds, the north coast has been defined as the Arctic coastal tundra ecoregion. Arctic Alaska is also the location of the Arctic National Wildlife Refuge, Gates of the Arctic National Park and Preserve, and the National Petroleum Reserve-Alaska. The Arctic experiences midnight sun in the summer and polar night in the winter. Arctic Alaska Arctic Alaska
Snow camouflage snow camouflage patterns. Charles Darwin mentioned the white winter coloration of the ptarmigan in his 1859 "Origin of Species": The white protective coloration of arctic animals was noted by an early student of camouflage, the naturalist Alfred Russel Wallace, in his 1889 book "Darwinism"; he listed the polar bear, the American polar hare, the snowy owl and the gyr falcon as remaining white all year, while the arctic fox, arctic hare, ermine and ptarmigan change their colour, and observed "the obvious explanation", that it was for concealment, at a time when Darwinism was at a low ebb. Later zoologists such