I.Arctogean Realm
Geographic limit:
Arctogean realm is called the "Northern land". It comprises North America up to Tropics of Cancer, Greenland, and the Northern half of the Old world which includes Palaearctic, Ethiopian and Oriental regions. It is the largest of the all realms but has least clear defined fauna.
Characteristics of fauna:
The main features of Arctogean fauna are:
1. It contain highest mammals and most specialised birds. the mammalian fauna includes even the most specialised ungulates and most advanced primates.
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| American opossum |
2. There are no monotremes and no marsupials (except: American opossum).
3. The primitive reptiles are not represented in this realm.
Arctogean fauna presents a remarkable homogeneity because of the land bridge between Asia and North America. Also there were no desert barrier as are present now which inhibit movement between Afro-Eurasian land mass. It is presumed that regionalisation of animal life with in Arctogean realm is due to recent geological events, especially during Pleistocene glaciation.
It can be subdivided into 3 regions:
2. Ethiopian Region
3. Oriental Region
