An international team of scientists has discovered evidence that Malaysia's "mystery monkey" is a cross between a proboscis monkey and a silvery langur. The group outlines their research of photographs of the monkey and how they arrived at their conclusion regarding its origins in an article published in the International Journal of Primatology.
In 2017, scientists in Borneo started receiving tales of a mysterious monkey living in Malaysian Borneo's woodlands near the Kinabatangan River. The monkey was thought to be a youngster at the time. Suspecting interspecies mating, the researchers started looking for mentions of the monkey on social media platforms, gathering images of the animal as they went. Unfortunately, because of pandemic limitations, they were unable to enter the woodland to investigate. Instead, they investigated the images they could receive.
The researchers noticed that the monkey was living in the same region as proboscis monkeys and silvery langurs. Proboscis monkeys are distinguished by their huge bulbous noses and pink features. The silvery langur, sometimes known as the silvered leaf monkey, is a lesser-known species. It has a dark face and a considerably smaller nose. The two monkey species are closely related yet vastly different in size. The proboscis may grow to 76 cm in length and weigh 20 to 24 kg on average. The langur, on the other hand, grows to about 56 cm in length and weighs around 6.6 kg.
The researchers discovered that the mystery monkey had a bulbous nose, but it was not quite as big as is typical for the proboscis. She also had an unusually colored face that was neither pink nor black, but rather ashy. Despite these distinctions, the researchers believe the mystery monkey is a hybrid between a male proboscis and a female langur. More shocking, she seems to have had children—in one shot, she is holding a newborn, and her breasts look engorged, implying she is the kid's mother. The majority of crossbred children are infertile.
According to the researchers, the crossbred monkey resulted from the two monkey populations being squeezed into ever-smaller habitats owing to oil plantation growth.