The Manas National Park harbours 61 species of mammals, 450 species of birds, 42 species of reptiles, 9 species of amphibians, 79 species of fishes and more than 200 species of butterfly and 100 species of invertebrates.
Manas NP supports one critically endangered, seven endangered, ten vulnerable mammals; five critically endangered, two endangered, eighteen vulnerable birds and four endangered and nine vulnerable reptiles.
- Mammals: The main carnivores of MTR are Tiger (Panthera tigris tigris), Leopard (Panthera pardus), Clouded Leopard (Neofelis nebulosa), Leopard Cat (Prionailurus bengalensis), Fishing Cat (Prionailurus viverina), Golden Cat (Catopuma temmincki), Jungle Cat (Felis chaus), Marbled Cat (Pardofelis marmorata), Himalayan Black Bear (Ursus thibetanus), Sloth Bear (Melursus unsinus), Mongoose (Herpestes edwardsi), Wild dog (Cuon alpinus), Hog badger (Arctonyx collaris), Civet Cat (Viverricula indica), Indian fox (Vulpes bengalensis), Jackal (Canis aureus) etc.
- Among the herbivores of Manas Tiger Reserve, the pre-dominants are Elephant (Elephas maximus), Wild Buffalo (Bubalus bubalis), great Indian one horned Rhino (Rhinoceros unicornis), Gaur (Bos gaurus), Sambar (Rucervus unicolor), Swamp deer (Cervus duvaucelli duvaucelli), Barking deer (Muntiacus muntjak), Hog deer (Axis porcinus), wild pig (Sus scrofa cristatus), Hispid Hare (Caprolagus hispidus). Other key mammals of the park are like golden langur, capped langur, slow loris, pygmy hog, Malayan giant squirrels and Chinese Pangolin (Manis pentadactyla) etc. (Annexure).
- Birds: The avifaunal diversity of Manas is very rich as confluence of wide range of habitats. Over 450 bird species has been recorded so far and Manas has been declared as one of the Important Bird Sites in India. Some of the globally threatened bird species of Manas are King Vulture (Sarcogyps calvus), Slender-billed Vulture (Gyps tenuirostris), White-rumped Vulture (Gyps bengalensis), White-bellied Heron (Ardea insignis), Bengal Florican (Houbaropsis bengalensis), Lesser Adjutant Stork (Leptoptilos javanicus), Swamp Francolin (Francolinus gularis), Manipur Bush Quail (Perdicula manipurensis), Eastern Imperial Eagle (Aquila heliacal), Greater Spotted Eagle (Aquila clanga), Pallas’ Fish Eagle (Haliaeetus leucoryphus), Rufous-necked Hornbill (Aceros nipalensis), Great pied Hornbill (Buceros bicornis), Pea Fowl (Pavo Cristatus), Marsh Spotted Babbler (Pellorneum palustre), Jerdon’s Babbler (Chrysomma altirostre), Black-breasted Parrotbill (Paradoxornis flavirostris), Slender-billed Babbler (Turdoides longirostris), Rufous-vented Prinia (Prinia burnesii), Rufous-rumped Grassbird (Graminicola bengalensis), Bristled Grass Warbler (Chaetornis striata), Hodgson’s Bushchat (Saxicola insignis), Finn’s Weaver (Ploceus megarhynchus) etc.
- Reptiles: Among reptiles, turtles, lizards, various kinds of Snakes such as King Cobra (Ophiophagus hannah), Banded Krait (Bungarus fasciatus), Monocellate Cobra (Naja kaouthia), Indian Python (Python molurus) and Burmese rock Python (Python molurus bivitattus), turtles such as Yellow Tortoise (Indotestudo elongate), Narrow-headed Softshell Turtle (Chitra indica), Assam Roof Turtle (Pangshura sylhetensis), Tricarinate Turtle (Melanochelys tricarinata), Malayan Box Turtle (Cuora amboinensis), in addition to that there are sporadic records of Gharial (Gavialis gangeticus) in Manas.
- Fishes: Numerous rivers and streams in the forests of this Reserve contain a variety of fish of which large size fishes are Tor putitora, Tor progenies, Tor tor, Ladeo boga, Ladeo gonius, Ladeo rohita, Ladeo calbasu, Wallago attu. There are innumerable small fishes in the rivers and streams. Most common are species are Puntius ticto, Botia Dario and Puntius tetrarupagus.
Distribution of wildlife
The large tracks of grasslands of Manas NP are some of the last remaining examples of Terai grasslands in the Indian sub-continent. These grasslands are the key sites for biodiversity conservation and is not only restricted as unique habitat but also support wide range of endangered fauna (Lahkar 2008). About 43% area of Manas National Park is cover by grassland habitat.
Out of 22 the mammals of Schedule-I, five (5) species are obligate to grassland where as nine (9) species are dependant partially on grassland habitat.
A total of 118 bird species has been recorded by Lahkar (2008) and out of 118 species recorded, as many as 95 species of birds were found to be resident. Out of 118 species of bird 33 species could be identified as ‘obligate grassland birds’. In eastern Himalayan biodiversity hotspot, there are 12 globally threatened associated with grassland habitat and all the species are found only in Manas National Park (Lahkar, 2008).