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A monkey researcher fights to protect threatened and endangered primates

Andie Ang and her long-tailed macaques.

Andie Ang is a primatologist at Mandai Nature, a research organization and funder in Singapore. Credit: James Chua

I was a ten-year-old in Singapore when I received a vervet monkey (Chlorocebus pygerythrus) as a pet. By the time I was 15, I knew that my family did not have the necessary international permit to own it legally. With help from local agencies, we sent the monkey to a rehabilitation sanctuary in Zambia, which ultimately released it into the wild. That experience got me interested in learning more about wild monkeys and how to help them.

I research threatened and endangered leaf-eating primates known as Asian colobinae. They have specialized, multi-chambered stomachs, as do cows, and need a long rest after meals. They are shy and hard to find, so there has been less research on them than on orangutans or the great apes.

One species I study is the critically endangered Raffles’ banded langur (Presbytis femoralis). Globally, there are just 320 individuals: 70 in Singapore and 250 in Malaysia. I work with national agencies, educational and non-governmental organizations and local communities to help protect these and other monkeys — especially those living between forest and urban areas. For example, in an area prone to roadkill, we installed a rope bridge to let langurs and other animals cross the road safely.

One of the biggest threats to these and other monkeys is inbreeding as their numbers shrink. We hope to exchange animals between Singapore and Malaysia to boost their population’s genetic health.

In this picture from 2017, I was monitoring primate populations in a reserve in central Singapore when I saw these long-tailed macaques (Macaca fascicularis). Here, we are observing one another — and respecting each other’s space.

I’ve started a website called Primate Watching to help observers learn about these primates and where to see them. People think monkeys are aggressive, but really they are just naturally curious. Still, the public should always keep a safe distance, not put a camera in their faces.

Nature 595, 618 (2021)



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