1 ) This region shows wide range of temperature fluctuations.
2) It also shows wide range of fluctuation in the amount of rainfall.
3) It includes polar arctic region.
4) On its Northern side it shows temperate conditions
5) Eastern Asia shows deciduous forests.
6) In the Northern region ‘Steppe’ grass lands are present.
Hence region shows wide fluctuations in physical and climatic features, so , it supports good fauna.
Sub regions: Palaearctic region has been divided into four sub regions.
1) European Sub-region : Northern and central Europe, Black sea and caucasus rare included in it. It is represented by 85 families of vertebrates. Amphibians and Reptiles are represented with six families each. Myogale, only one genus of mammal is present. Bird like Tits, wagtails, mammals like wolf and moles are common in this sub-region.
2) Mediterranean Sub region : Remaining parts of Europe; Africa and Arabian portions are included in it. 124 families of terrestrial vertebrates are present. Birds like Upupa and Pastor, mammals like elephant scurew, Hyaena and porcupine are seen in this sub-region.
3) Siberian sub region : Northern Asia, Himalayas are included in it. 94 families of vertebrates are included in it. Families of Musk deer and Moles are ccnfined to this sub-region.
4) Manchurian Sub region : Mangolia, Japan, Korea, and Manchuria are included in it. Mammals like, Tibetan Langur, Great Panda, Tufted deer, Chinese water deer are common.
Fauna : This region is supported by good fauna. Fishes, Amphibians, Reptiles, Bijds and Mammals are represented.
Fishes : Most of the fishes show greater affinity to North America. Paddle fishes in China, Cyprinus, Anabas and Sucker fish (Echenis) are present.
Amphibians : Frogs like Discoglossus, Bufo, Hyla, Rhacophorus, Salamanders like Proteus, Megalobatrachus, and a number of tailed am- phibians are seen in palaearctic and Nearctic regions.
Reptiles : Snakes like Natrix, Dasypettis, T,rphlos, lizard like Monitor, tortoise like Testudo are common. True pit vipers, Colubrids are most commonly seen. ‘
Birds : Birds like Hawks, Cukoos, rails, finches, crows are present which are migratory. Nearly 37 species of birds are present. Parrots are absent.
Mammal. : Camel, deer, wolf, horse, pig, hedgehog like mammats are common, Fruit bats, panthera bear are also present. The common mammalian fauna includes Deer, Beavers, Dog, Cat, Squirrels, Rabbits, Mice, Bats and moles.
Therefore, it clearly suggests that vertebrate fauna of palaearctic region is not very rich and shows overlapping nearctic region with New world and old world fauna.