Field Journal: Lorises After Dark

by AMNH on

From the Field posts

Mary Blair, assistant director for research and strategic planning at the Museum’s Center for Biodiversity and Conservation, is blogging from the field during this summer’s expedition to Vietnam. Read about her 2013 expedition here.

Pygmy slow loris sits on a tree branch and peers through the leaves.
Pygmy slow loris in Lam Dong Province, Vietnam.
© T. Mai Hoàng

The night is dark and full of… lorises? At least, that’s what we hope as we search for these small, nocturnal primates here in central Vietnam. 

Right now, we’re working alongside our Vietnamese colleagues in two protected forests in the region to collect essential data that addresses basic questions about lorises. How many different species are there, and how can we tell them apart? Where do these populations come from, and how many remain? Conservation managers will need these answers to protect these species more effectively from further population decline.  

Lush hills full of grass and trees, with coastline visible in right background.
Son Tra Nature Reserve is a peninsula off the coast of the Central Vietnam city Da Nang.
© Mary Blair

Mostly because of their size and schedule, both of which make them difficult to investigate in the wild, lorises are among the least studied primates in Southeast Asia. Our small but growing global community of slow loris researchers is working to perfect techniques to find and follow these elusive animals. That means becoming nocturnal, like the animals we’re trying to find.  

In our night surveys, teams of three to four people walk very slowly and as quietly as possible. Team members are spaced about 30 feet apart, scanning all levels of vegetation using bright headlamps with red filters. These red filters allow us to not only preserve our own night vision, but to detect the characteristic orange ‘eyeshine’ of a loris from very far away.

When we spot a loris, one of us shines a halogen spotlight on the animal while another uses binoculars or a camera with telescopic zoom to get a better look to confirm the species. We look for the color of the nose and the ears, the size of the animal, and for any facial markings, such as stripes or patches of dark colors, which help us to tell species apart. 

Four adults standing outdoors on brown rocky dirt near a motorcycle. Captions reads: “Preparing our equipment before our night survey in Bach Ma National Park.”
Preparing equipment before our night survey in Bach Ma National Park.
© Thạch Mai Hoàng

Of course, we have to be prepared. Before we go out at night, we rehearse during the day to go over signals, spacing, team assignments, and duties. Coordination between team members is extremely important to ensure that if we see an animal, it doesn’t get away without being photographed.

Cameras are far from our only tools, though. In addition to headlamps and flashlights to help find our way, team members also carry walkie talkies, weather and moonlight meters, laser rangefinders, GPS units, leech socks (very important), first aid kits, plus the all-important water and late-night snack. Personally, I’m rarely caught in the field without a little chocolate. 

Giant Asian forest centipede on a branch at night in Bạch Mã National Park in Vietnam.
Giant Asian forest centipede (Scolopendra subspinipes) sighted during our night survey in Bach Ma National Park.
©Mary Blair

But you can’t prepare for everything. The forest looks, sounds, and feels completely different at night than it does during the day, as it comes alive with huge centipedes, frogs, and lizards, to name just a few. As a former daytime primatologist, though, I have to say I have quickly come around to the “dark side” of studying primates. 

Although we have not yet seen any lorises on our trip, we know from interviews with local community members that they are here—so we will continue our search! Stay tuned.