Palearctic realm

The Palearctic (or Palaearctic) is the world's largest biogeographic realm. Confined largely to the Eastern Hemisphere, it stretches across Europe and Asia, north of the foothills of the Himalayas, and North Africa. The realm consists of several bioregions, including Europe, the Mediterranean Basin, North Africa, North Arabia, Western, Central, North and East Asia. The Palaearctic realm also has numerous rivers and lakes, forming several freshwater ecoregions. Both the eastern and westernmost extremes of the Palearctic span into the Western Hemisphere, including western Europe (Iceland south to Portugal), Macaronesia, and northwestern Africa (Morocco) in the west, and Cape Dezhnyov in Chukotka Autonomous Okrug to the east. The term was first used in the 19th century, and is still in use as the basis for zoogeographic classification.