Greenland is the largest island in the world and is covered by the second largest ice cap in the world, Indlandsisen. Due to the large coverage of Indlandsisen (1,676,000 square kilometers [647,107 square miles] of the total 2,176,000 square kilometer [840,158 square mile] area of Greenland) only 18% of the island is ice free. The ice cap has an enormous influence on the climate and hydrology of the ice free land, which distinguishes it from the High and Low Arctic tundra of the US and Canada. Vascular plant species in the tundra of Greenland is divided into eastern and western affinities (Eurasian and American species, respectively). The caribou, arctic hare and arctic fox are the only three species to colonize the majority of Greenland.