Biological division of the Earth's surface (i.e. a large geographical area) containing a fauna more or less peculiar to it. The degree of distinctiveness varies with the region concerned and reflects partly climate and partly the existence of barriers to migration. The number of realms recognized varies from one authority to another, but a minimum of six are recognized: Australian, Ethiopian, Nearctic, Neotropical, Oriental, and Palaearctic.
Subjects: Earth Sciences and Geography.