Primatologists have suggested rerouting a 1.65-km-long railway track that divides the Hollongapar Gibbon Sanctuary located in eastern Assam. This sanctuary, dedicated to the western hoolock gibbon, is currently divided into two unequal parts due to these tracks, significantly impacting the natural habitat and behavior of the gibbons.
The Smallest and Fastest of All Apes: Hoolock Gibbons
Known as the smallest and fastest of all apes, the Hoolock Gibbons predominantly inhabit tropical and subtropical forests in Southeast Asia. They are highly intelligent and are known for their distinct personalities and strong family bonds, similar to other apes.
There are 20 gibbon species globally, and Hoolock gibbons are India’s only ape species. Within India, two types of hoolock gibbons are found—the western hoolock gibbon and the eastern hoolock gibbon. Both species are listed on Schedule 1 of the Indian (Wildlife) Protection Act 1972.
Western vs. Eastern Hoolock Gibbon: Where Do They Live?
The western hoolock gibbon inhabits states of northeastern India between the Brahmaputra River in the south and the Dibang River in the east. Outside India, it can be found in eastern Bangladesh and northwest Myanmar. Due to the decreasing numbers, this species is classified as “Endangered” by the International Union for Conservation of Nature’s Red List (IUCN).
The eastern hoolock gibbon is found in specific regions of Arunachal Pradesh and Assam in India. They also reside in southern China and northeast Myanmar outside India. This species is classified as “Vulnerable” by the IUCN Red List.
Unique Characteristics and Lifestyle
Hoolock gibbons are recognized for their distinct white eyebrows, long arms, and a throat sac used for vocalizations. They are exclusively arboreal, meaning they spend their lives in the treetops of tropical forests. However, these gibbons are particularly sensitive to habitat disruptions, such as canopy gaps, which can fragment their habitat leading to genetic isolation and threatening their survival.
Conservation efforts have been made to address these problems. Some initiatives, such as creating artificial canopy bridges, aim to facilitate the gibbons’ movement across the forest, helping preserve their genetic diversity.
The Role of Gibbons in Forest Ecosystems
Gibbons play a crucial role in forest ecosystems as they scatter seeds while travelling through the tree canopies, assisting with forest regeneration and maintaining biodiversity. As such, the conservation of gibbons is essential for the overall health of their habitats.
Hoollongapar Gibbon Sanctuary: A Beacon of Biodiversity
Formerly known as the Gibbon Wildlife Sanctuary, the Hoollongapar Gibbon Sanctuary in Assam’s Jorhat district houses India’s only gibbons—the western Hoolock hoolock. Established in 1997, the sanctuary also houses the Bengal slow loris, the only nocturnal primate found in Northeastern India.
Details about UPSC Civil Services Examination Queries
In previous years, questions concerning the hoolock gibbon and its adaptation have appeared in the UPSC Civil Services Examination. This includes a query regarding which protected areas are known for which species–a correctly matched pair being “Eravikulam, Kerala: Hoolock Gibbon”. Another question was on categorizing gibbons, gorillas, langurs, and orangutans as either apes or not. The correct answer was that gibbons are apes, while langurs are not.
Gibbons vs. Langurs: Identifying Differences
Gibbons and langurs have different classifications within the simian family. While both belong to the primate branch, Gibbons fall under the category of apes, whereas langurs are classified as Old World monkeys. One distinguishing feature is the presence or absence of a tail—apes like gibbons do not have tails, while monkeys like langurs do. In addition, langurs are typically smaller and narrow-chested, while gibbons are larger with broad chests and shoulder joints that allow them to swing through trees.