Species richness for the different classes of vertebrates in sikkim are:

Groups

Species Richness

Comments

Fish

48

9 families, genera, many of commercial importance

Amphibians

16

preliminary checklist only

Reptiles

26

preliminary checklist only

Birds

550

26 threatened (Birdlife International),9 of unknown distribution

Mammals

144

39 rare or endangered(Schedule 1 Indian Wildlife Protection Act,1991).

The butterfly species with known distributional ranges within sikkim belongs to five families. At present, 25 species of butterflies of Sikkim Himalaya have been listed in the high conservation priority Schedule I of the indian Wildlife (Protection) Act amended up to 1991 and another 300 species in Schedule II category.