Itanagar Zoo’s vital role in saving Hoolock Gibbon

By Pradeep Kumar

ITANAGAR, July 07: First Hoolock Gibbon conservation-cum-breeding centre of India, fully funded by Central Zoo Authority (CZA), was launched in Itanagar Biological Park, popularly called Itanagar Zoo, spread in over 250 hectares, after the lesser apes’ population during a survey conducted in 2006-07 was estimated to be around 600 in the wild, said zoo curator Raya Flago.

Advanced technology was not available then and camera trapping was used then in this geographically vast Himalayan state and accurate survey of wildlife even now is next to impossible, he said, adding another estimate put the present population of Hoolock Gibbon in wild at approximately 1500. The Hoolock Gibbon conservation-cum-breeding centre is still operational, he disclosed in an exclusive interview to this daily on Friday.

Present Hoolock Gibbon population of Itanagar zoo is 18 – male (9), female (4) and 5 (unidentified), he said, adding the genders of new-born gibbons could be identified only after four years through morphological changes in their skin colour. The baby gibbons are kept under 15-day observation, which is very crucial period for their survival, he informed.

It may be recalled here that a female gibbon was brought from Roing in Lower Dibang Valley district in 2008 and named ‘Mishmi Baido’ (Mishmi sister) and 17 gibbons were born in the facility since 2008, of which only three had died.

‘Mishmi Baido’ had given birth to a baby gibbon on 07.10.15. Its partner was named ‘Corneal Opacity’ because of his defective eyes, Flago said, adding two Eastern Hoolock Gibbons (Hoolock leuconedys) were born within eight days in December 2020.

The first baby was born to the zoo’s youngest couple ‘Jesu’ and ‘Sonu’ on 12.12.20 and the second to ‘Bhat’ and ‘Yapa’ on 20.12.20 and another was born in September 2021 and named ”Gandhi”.

Hoolock gibbon is the only primate species in the country and state animal of Arunachal Pradesh, but highly endangered species, Flago said, adding “It is our prime duty to save this beautiful animal from extinction.”

Hoolock Gibbon is a unique primate species found only in seven Northeast states India. Western Hoolock Gibbon is listed as Endangered and Eastern Hoolock gibbon as Vulnerable in IUCN Redlist. In India, both western Hoolock gibbon and Eastern Hoolock gibbon are listed on Schedule 1 of the Indian (Wildlife) Protection Act 1972.

Flago lauded Aaranyak, a leading biodiversity conservation organisation of NE, for launching a Hoolock Gibbon conservation campaign in Arunachal Pradesh to educate the public and future stewards about importance of conservation of Hoolock gibbon in the greater interests of preserving forest cover and biodiversity.

The campaign began with a programme at Wakro Govt secondary school, followed by campaign in Apna Vidya Bhavan and Kasturba Gandhi Balika Vidyalaya and Don Bosco School.

Aaranyak’s Primate Research and Conservation Division had worked together with the Arcus Foundation and Kamlang Tiger Reserve authority for the campaign. The campaign from June 29 to July 1 had concluded with distribution of poster, stickers and book on the Hoolock gibbon.

Hoolocks are the second-largest of the gibbons, after the Siamang and reach a size of 60 to 90 cm and weigh 6 to 9 kg. The sexes are about the same size, but they differ considerably in coloration: males are black-colored with remarkable white brows, while females have a grey-brown fur, which is darker at the chest and neck. White rings around their eyes and mouths give their faces a mask-like appearance. The name Hoolock, as per Oxford English dictionary, is from the Assamese   (holou) or related languages.

Young hoolocks are born after a 7-month gestation, with milky white or buff-colored hair. After about 6 months, the hair of males darkens and turns black, while the females’ hair remains buff-colored throughout their lives. After 8–9 years, they are fully mature and their fur reaches its final coloration. Their life expectancy in the wild is about 25 years.

The classification of this gibbon has changed several times in the past few years. Classically, all gibbons were classified in the genus Hylobates, with the exception of the siamang. After some studies, the genus was divided into three subgenera (including the Siamang’s Symphalangus), and then into four (recognizing Bunopithecus as the hoolock subgenus distinct from other gibbon subgenera).

These four subgenera were elevated to full genus status. However, type species for Bunopithecus is Bunopithecus  sericus, an extinct gibbon or gibbon-like ape of Sichuan, China. Very recent investigations have shown that the hoolock gibbons are not closely related to Bunopithecus  sericus, so they have been placed in their own genus, Hoolock. In the process, the two subspecies of hoolock gibbons have been raised to species level.

A new subspecies of the western hoolock gibbon has been described recently from NE India, which has been named the Mishmi Hills hoolock gibbon, H. hoolock mishmiensis. A further new species, H. tianxing, with an estimated population of about 200, was discovered in southwest China in 2017.

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