Explanation:

Hoolock Gibbons:

The forests of north-east India support the highest diversity of primates in India, including the only apes found in the country, the western hoolock gibbon (Hoolock hoolock) and the eastern hoolock gibbon (Hoolock leuconedys).

Often confused as one species, both the gibbons inhabit different ranges in India.

The western hoolock gibbon has a much wider range, as it is found in all the states of the north-east, restricted between the south of the Brahmaputra river and east of the Dibang river. Outside India, it is found in eastern Bangladesh and north-west Myanmar.

The eastern hoolock gibbon inhabits speci fi c pockets of Arunachal Pradesh and Assam in India, and southern China and north-east Myanmar.

Of the two, the western hoolock is listed as Endangered in the IUCN Redlist, while the eastern hoolock is listed as Vulnerable.

Orangutan:

The name orangutan means “man of the forest” in the Malay language. 

In the lowland forests in which they reside, orangutans live solitary existences.

They make nests in trees of vegetation to sleep at night and rest during the day.

Known for their distinctive red fur, orangutans are the largest arboreal mammal, spending most of their time in trees.

These great apes share 96.4% of our genes and are highly intelligent creatures.

Gorilla:

Gorillas are gentle giants and display many human-like behaviors and emotions, such as laughter and sadness.

Gorillas share 98.3% of their genetic code with humans, making them our closest cousins after chimpanzees and bonobos.  They are largest of the great apes.

They live mostly in the Congo basin area.