Arunachal Pradesh has among the highest diversity of mammals and birds in India.
There are around 750 species of birds and more than 200 species of mammals in the state.

In the year 2000 Arunachal Pradesh was covered with 63,093 km² (24,360 sq mi) of tree cover (77% of its land area).
Arunachal's forests account for one-third of habitat area within the Himalayan biodiversity hot-spot.
In 2013, 31,273 km² (12,075 sq mi) of Arunachal's forests were identified as part of a vast area of continuous forests (65,730 km² or 25,380 sq mi, including forests in Myanmar, China and Bhutan) known as Intact forest landscapes.
It harbours over 5000 plants, about 85 terrestrial mammals, over 500 birds and many butterflies, insects and reptiles.
At the lowest elevations, essentially at Arunachal Pradesh's border with Assam, are Brahmaputra Valley semi-evergreen forests.
Much of the state, including the Himalayan foothills and the Patkai hills, are home to Eastern Himalayan broadleaf forests.
Toward the northern border with Tibet, with increasing elevation, come a mixture of Eastern and Northeastern Himalayan subalpine conifer forests followed by Eastern Himalayan alpine shrub and meadows and ultimately rock and ice on the highest peaks.
It supports many medicinal plants and within Ziro valley of Lower Subansiri district 158 medicinal plants are being used by its inhabitants.
The mountain slopes and hills are covered with alpine, temperate, and subtropical forests of dwarf rhododendron, oak, pine, maple and fir.
The state has Mouling and Namdapha national parks.

A new subspecies of hoolock gibbon has been described from the state which has been named as Mishmi Hills hoolock H. h. mishmiensis.
Three new giant flying squirrels were also described from the state during the last one and half-decade.
These were, Mechuka giant flying squirrel, Mishmi Hills giant flying squirrel, and Mebo giant flying squirrel.
Arunachal Pradesh has among the highest diversity of mammals and birds in India. There are around 750 species of birds and more than 200 species of mammals in the state.
In the year 2000 Arunachal Pradesh was covered with 63,093 km² (24,360 sq mi) of tree cover (77% of its land area). Arunachal's forests account for one-third of habitat area within the Himalayan biodiversity hot-spot. In 2013, 31,273 km² (12,075 sq mi) of Arunachal's forests were identified as part of a vast area of continuous forests (65,730 km² or 25,380 sq mi, including forests in Myanmar, China and Bhutan) known as Intact forest landscapes. It harbours over 5000 plants, about 85 terrestrial mammals, over 500 birds and many butterflies, insects and reptiles. At the lowest elevations, essentially at Arunachal Pradesh's border with Assam, are Brahmaputra Valley semi-evergreen forests. Much of the state, including the Himalayan foothills and the Patkai hills, are home to Eastern Himalayan broadleaf forests. Toward the northern border with Tibet, with increasing elevation, come a mixture of Eastern and Northeastern Himalayan subalpine conifer forests followed by Eastern Himalayan alpine shrub and meadows and ultimately rock and ice on the highest peaks. It supports many medicinal plants and within Ziro valley of Lower Subansiri district 158 medicinal plants are being used by its inhabitants. The mountain slopes and hills are covered with alpine, temperate, and subtropical forests of dwarf rhododendron, oak, pine, maple and fir. The state has Mouling and Namdapha national parks.
A new subspecies of hoolock gibbon has been described from the state which has been named as Mishmi Hills hoolock H. h. mishmiensis. Three new giant flying squirrels were also described from the state during the last one and half-decade. These were, Mechuka giant flying squirrel, Mishmi Hills giant flying squirrel, and Mebo giant flying squirrel.
Arunachal Pradesh