Is ‘mystery monkey’ in Sabah forest an incredible hybrid?

KOTA KINABALU – A “mystery monkey” seen in Sabah, believed to be a hybrid of two distantly related primates, has taken researchers aback, and they believe the case may be linked to habitat loss and fragmentation of forests. 

The strange-looking monkey may be an interspecies hybrid between a proboscis and the silvery langur, they claim.

Sightings of the monkey along Sg Kinabatangan were uploaded on social media wildlife photography groups in 2017. 

Studies are being done based on various photographs taken of the monkey. The measurements of limb proportions show characteristics of the proboscis monkey (Nasalis larvatus) and the silver langur (Trachypithecus cristatus). 

Multiple observers have confirmed the occurrence of such mixed-species groups in the area and interspecific mating. 

Researchers believe the case may be related to habitat loss and fragmentation as oil palm plantations have expanded in the state, confining the two putative parent species to narrow riverine forest patches along the river. 

Interspecies mating can occur when groups of both parent species are confined in small spaces, said Nadine Ruppert, a primatologist and senior lecturer at Universiti Sains Malaysia, who co-authored a paper on the subject in the International Journal of Primatology in April.But Ruppert admits further research is needed to examine the area where the primates regularly travel in search of food or mates, which suggests overlap with those of neighbouring animals or groups of the same species.

The mystery monkey has been spotted on at least three different occasions between June 2017 and November 2018 near Kg Bilit, a village along Sg Kinabatangan. 

A veterinarian who has been working with wildlife and primates in Sabah for some 20 years said interspecies breeding can happen in many cases.  

“One of the factors could be the sharing of habitat or shrinking of habitat which could be happening in Kinabatangan, where the primates are forced to share the habitat.  

“It could be due to a lone primate monkey who had lost his harem and may have wandered into the home range of another species,” he said, adding that he also had come across an interspecies hybrid of the long-tail macaque in 2016. 

The veterinarian, however, believes there is a need to be definitive on what species the monkey belongs to, and this would have to be done through studying biological samples. 

“A proper genetic analysis can be done to determine the species and give a definitive answer if it is a hybrid or not,” he said. 

Sabah Wildlife Department Director Augustine Tugga meanwhile said he had no comment on the issue but advised researchers to conduct their research thoroughly to confirm their findings rather than speculating that the “mystery monkey” is the result of habitat loss and fragmentation. – The Vibes, June 13, 2022