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Call of the Orangutan: How to Find an Orangutan

The views expressed are those of the author and are not necessarily those of Scientific American.


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While many animal researchers use fancy scientific methods to analyze data and samples they’ve collected, the mechanics of virtually every animal behavior study begins with finding an animal or animals and recording its or their behavior at a given interval to produce what’s called an ethogram. So, in this blog I’ll be running through the process of finding an orangutan, and in the next one I’ll write about what we do during a “follow”.

Search days are fun! Everyone likes them because you get a lie-in and a nice walk in the forest. Every field site I’ve worked at schedules the start for 8 a.m., although I have yet to witness a search that hasn’t started late! At any rate, it’s vastly better than having to get up at 5 a.m. (and sometimes as early as 4 a.m.) for full-day follows, and I’m certainly one of the worst offenders when it comes to lateness!

At 8:15 a.m. the author is the first to be ready for a search day.

Once everyone has finally got him or herself ready, we’ll meet to discuss where we’re going to search for the day. Here at the Sikundur research station in North Sumatra, this happens in front of the trail map posted on the verandah.

Sikundur has a grid system, which is great, as you can pick a pattern that ensures you cover your target area thoroughly and shouldn’t miss any individuals. Typically at the morning meeting, the Indonesian field assistants will propose an area of the grid close to camp in a flat area, and I’ll respond with a proposal to search an area far away and with lots of hills.

Camp manager Suprayudi discusses the day's search strategy with field assistant Supri.

After much complaining and joking from both sides, plus useful input about encounters with animals, new nests and signs of feeding, a compromise is usually reached. We’ll either search in a hilly area or far away, but not both. That said, fairly often we’ll all agree to search close to camp, especially if we’ve been following an animal out on the boundaries the week before. Or I’ll push for a specific area if we’ve heard a male making long calls (vocalizations meant to attract mates) from that direction or there’s a specific animal we’re looking for.

Trail map for the Sikundur research station. (Courtesy of Matthew Nowak, Sumatran Orangutan Conservation Programme)

Orangutans are exceptionally difficult to study because they live in low densities and are widely dispersed in thick jungle habitats, all of which influence our strategy for searching. Ideally in the forest we use radios or cell phones to keep in contact while each person searches individually on a given route. However, until I learn the trails at this new site or we get some radios (donations gratefully accepted!), we’re currently using a slightly different method. We split into teams of two and one member from each pair will walk out 50 to 100 meters along a transect while the other remains behind for about five minutes. This should ensure you don’t miss any animals due to making too much noise, while still maintaining a close enough distance that you can shout if you lose the transect (easy to do in dry forest).

The plan is for each person to creep along the path looking for any new nests or discarded fruit and, most importantly, to stop regularly to listen for the telltale signs of an orangutan: the crunch of fruit being eaten, a branch breaking in the distance or, if you’re really lucky, a long-call, which facilitates easy localization from far away. However, until you get your “jungle legs” this is all much easier said than done! At first, most of your time is spent watching your feet, crashing through the undergrowth, falling into streams and missing any signs of an orangutan. Meanwhile, the field assistants seem to float across the jungle floor, never missing a step regardless of the terrain. Later, they’ll ask if you saw the nest, discarded fruit or clouded leopard that you inevitably missed because you’d grabbed a branch that wasn’t strong enough to hold your weight and crashed into a beehive.

Field assistant Ben searches for an orangutan at location A425 on the Sikundur grid.

You’d think that to find an animal as large as an orangutan sight would be your most important sense, but it’s actually much easier to listen for them. However, the jungle is incredibly noisy! In the mornings, groups of siamangs (listen below) and gibbons will unleash their haunting calls, which carry up to a kilometer across the jungle canopy. In addition, a bewildering array of different birds sing and call, while insects produce a cacophony of noise that seems entirely disproportionate to their size, especially the incredibly annoying “chainsaw” bugs.

 

 

Speaking of chainsaws, our ability to locate orangutans has also been diminished by constant illegal logging in the southeast corner of the study site, a region frequently used by orangutans and very much within Gunung Leuser National Park. No matter how much we complain no one from the park seems to want to deal with the problem. Our plan is to check it out once the loggers leave, and I’m sure it will be an interesting topic for a future blog post.

Moving back to more pleasant matters, despite the difficulties inherent in finding orangutans, it is possible! The key thing is to stop regularly on your search, as the orangutans will sit very still when they see you and only resume their activity after a little while. Gradually, with a little practice, you stop missing your steps and start to pick out all the little clues that help in finding an individual (although I’ve lost count of how many times I’ve gone to an “orangutan” only to find it was elephants, macaques, a sun bear or just my imagination).

Finding an orangutan feels like an awesome achievement, whether you’ve cunningly tracked it down by following discarded fruit and a single crunch from 200m to your Northeast or you’ve simply stopped to take a leak and the animal has just appeared overhead with you none the wiser. However, it always seems that no one else is quite so excited, probably because they all know it’s going to be an extremely early start the next day, and thirteen-plus hours following the animal no matter where it goes or how much it rains.

James Askew About the Author: James Askew is a PhD candidate in Integrative and Evolutionary Biology at the University of Southern California Jane Goodall Research Center. His research is focused on orangutan behavior, specifically the “long call” and its role in social and reproductive relationships. Over the next 18 months he will be running a comparative study of three different populations at sites in Borneo and Sumatra. Follow on Twitter @jinborneo.

The views expressed are those of the author and are not necessarily those of Scientific American.





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  1. 1. Robert007 10:22 am 08/18/2014

    Sounds like hard work for sure but seeing these creatures in the wild is still definitely on my to do list!

    Link to this

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