Study reveals Malaysia may house two distinct subspecies of white-handed gibbon

A file picture of a white-handed gibbon in the Kuala Langat North Forest Reserve. – ZAHARIL DZULKAFLY

PETALING JAYA: A local study on white-handed gibbons in the country may have led to the discovery of a distinct subspecies that may have evolved in isolation.

The study, which was published in the peer-reviewed journal ZooKeys in December, was conducted by scientists from the Wildlife and National Parks Department (Perhilitan), Universiti Putra Malaysia, Universiti Malaysia Sarawak and Universiti Kebangsaan Malaysia.

Genetic assessment was conducted on 12 gibbons which had been either rescued, surrendered or seized from illegal pet trade, private collectors and plantations from different parts of Peninsular Malaysia.

The team discovered that the gibbons from the southern population of Peninsular Malaysia had unusual mutations compared to the northern population.

The southern population were gibbons found south of Sungai Perak, whereas the northern population lived north of Sungai Muda in Kedah.

The space in between the two rivers were inhabited by another gibbon species, the black-handed gibbon.

As per the requirement of Perhilitan’s Primate Rehabilitation Programme, captive gibbons must undergo a series of procedures and assessments where their taxonomy and genetics would be examined before they could be released into the wild.

“Therefore, the study will help with the plans for the translocation and reintroduction program to release the white-handed gibbons, particularly those which were surrendered or confiscated, into their original habitat,” Perhilitan said in a post on social media.

“The distinguishable differences between the postulated northern and southern populations warrant their treatment as separate management units (MU), a component within the Evolutionary Significant Unit (ESU),” the study read.

Although treated as separate MU, under the circumstance that the remnant populations of white-handed gibbons are showing signs of inbreeding depression or increased fragmentation, mixing (translocation) between MU are permissible,” it added.