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| Photo: Perry van Duijnhoven |
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This report was filed by Dr. Serge Wich, a visiting scientist on the staff at Great Ape Trust of Iowa from Utrecht University in the Netherlands. He has studied orangutans in the wild for years and recently embarked on a three week research expedition to Sumatra.
This is Dr. Wich’s second in a series of two dispatches:
Back to Batang Toru
After the exciting time at the Ketambe research site, we headed to Medan to prepare for the second portion of our visit. This trip would lead to the Batang Toru area, which is located southwest of Lake Toba. The lake is a silent reminder of a giant volcanic eruption that took place 74,000 years ago. Gabriella Fredriksson who conducts the conservation activities in the area for the Sumatran Orangutan Conservation Programme (SOCP), led this trip on which photographer Perry van Duijnhoven and I would visit the new research camp built there, in part, with support from Great Ape Trust of Iowa.
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| Photo: Perry van Duijnhoven |
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I was extremely excited about returning to the Batang Toru area. It was five years ago that Tine Geurts (my wife, who is now part of the orangutan research program at Great Ape Trust), Dr. Sri Suci Utami Atmoko, Dr. Ian Singleton and I conducted surveys throughout Sumatra for the Golden Ark Foundation. Historically, and until at least the early 1960s, orangutans had been found south of Lake Toba, but after that the scanty reports of orangutans south of Lake Toba had not been checked and the occurrence of orangutans there was far from certain. One of the pioneers of orangutan research and conservation, Dr. Herman Rijksen, was very interested in determining whether orangutans still occurred there because it might provide new opportunities for their conservation. Earlier surveys by Erik Meijaard provided some clues that orangutans perhaps still habituated some of the areas we were surveying at that time. After months of criss-crossing Sumatra on bumpy roads in old buses and motorbikes (only to discover the forests we hoped would contain orangutans were unfortunately empty), we came to the Batang Toru area. Basically it was going to be the last area that Tine and I would visit before returning to Medan with the bad news that there were no orangutans left south of Lake Toba.
All throughout the surveys Tine and I conducted five years ago, we had met friendly and extremely hospitable people that would provide us with the best they could offer, which in small villages was often not more than a wooden floor as a bed and a plate of rice with some deep-fried fish with more bones than meat. Combined with long forest walks this was slowly depleting our reserves. Thus rather exhausted after months of traveling and living in rather primitive conditions, we climbed the mountains of the Batang Toru area. After going uphill for two hours in the morning fog, we came to a little valley. There, directly in front of us was a nest. In slight disbelief we looked at each other and examined it carefully though our binoculars. There could only be one conclusion, this was a nest made by an orangutan. This was clear proof that orangutans occurred here. Immediately we were wondering how large the area would be where they were habituated. In the coming days, and on a follow-up survey a few months later, we discovered there were probably 400 to 600 orangutans in the area. That meant the population was very likely a viable one and conservation efforts were needed since only a small part of this forest was protected and the remainder was part of a large logging concession.
Heading for Camp
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| Photo: Perry van Duijnhoven |
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Now, five years after that first nest sighting, Gabriella is leading a multi-donor conservation program (that includes SOCP, Golden Ark Foundation, BOS-Netherlands, Great Ape Trust and others), in the area. The goal is to expand the protected area of the forest so this orangutan population – as well as tigers, tapirs and other species, will remain here.
To reach the area we took a small plane from Medan to the coastal town of Sibolga where we would buy supplies for our trip. After buying our basic ingredients for the trip: rice, noodles, and canned sardines, we set off for the forest. The area where the camp is located is in the northwest of the forest block and is surrounded by high ridges of a caldera, an ancient exploded volcano. To cross the ridge we first rented a small bus to take us and our gear to the last village – which was little more than a few houses and a large church. From there, we had to climb the last part of the ridge before descending to the camp located on the crater floor. The first part of the climb led through rice paddies after which a very muddy path wound up the ridge where small farms slowly made way to the primary rainforest block where the camp was also located. It was a welcome relief to go from the hot farmland to the coolness of the forest. However, more cool weather arrived as dark clouds turned into a strong tropical downpour – forcing us to grab our gear and scramble for cover under raincoats. Despite the storm, we kept slowly climbing the narrow and muddy trails. By now, our shoes were big lumps of mud that became heavier with each step. Our Indonesian staff cracked a popular joke that on muddy climbs such as this, one step up leads to two steps sliding down.
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| Photo: Perry van Duijnhoven |
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Finally, after three exhausting hours we reached the top of the ridge and took a short break to prepare for the descent to the crater floor and our camp. Although I do not mind climbing, the descent felt like a relief as the backpack was slowly getting too heavy for comfort. As we descended, the slightly dryer forest slowly made way to a moss forest – which is one of the most amazing forest types I have ever seen. The trees still stood tall, but many were covered with thick layers of moss which, with incoming sunlight, created some spectacular views.
Once on the crater floor, the walk became a stroll and we quickly headed toward our camp. But before reaching camp there was one more river to cross – one with a gorgeous waterfall. As you would expect, our photographer Perry had to make one last photo stop and carefully prepare his tripod and camera to capture this magnificent view. One more little climb and we caught the first glimpse of our camp, nestled alongside a crystal-clear river.
Surveying the Area
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| Photo: Perry van Duijnhoven |
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It felt great to reach our destination and unload our heavy packs. We were exhilarated knowing we would spend the next few days in this amazing setting. Gabriella explained to us that the camp was built after a series of detailed nest censuses showed the area’s highest orangutan density was in this very spot. The camp was more than adequate to fill our basic needs. It consisted of three houses on stilts with bamboo walls and roofs made of leaves. On the floor were wooden poles laid side by side covered with a layer of bamboo. With the thin, foam camping mattresses we brought with us, we would sleep comfortably.
As always in these basic camps the bathroom is the cold mountain river. I have to admit that on our first day I did little more than a quick wash of the face, or cowboy wash as some Indonesians call this, as it was already late in the afternoon. Then it was time for a hot mud-coffee and the first of our many meals of rice, noodles, and sardines. As our day ended, it felt good to be there and I was looking forward to exploring the area.
The next morning, I was awakened at daybreak by a chorus of agile gibbons. Since one of my interests is primate vocalizations, I quickly crawled out of my fleece sleeping bag, put on some trousers, my still very wet shoes and ran into the forest toward the direction of the singing gibbons. After a short climb, I was close enough to catch a glimpse of them in the far distance and start recording. The morning chorus lasted for about 30 minutes and I was very happy to have captured their vocalizations.
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| Photo: Perry van Duijnhoven |
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Following a very familiar breakfast of rice, noodles and sardines, we headed into the forest to look for orangutans and other primates. Although we saw quite a few nests we did not see any orangutans – fortunately we did see more gibbons and siamangs. This was not unexpected as it is difficult to find unhabituated orangutans due to their low densities and shy nature. It was also a good day to examine some of the tree species in the area and get an impression of how many held potential orangutan food. I was pleased to see several tree species that I had not expected – including ones that provide orangutans with food. One of the species is Neesia, a fruit bearing tree in which orangutans have been observed using tools to obtain the fruit seeds.
These tool-use studies have been reported extensively from the swamp forests on the West coast of Aceh by Dr. Carel van Schaik of the University of Zürich. However, several months previous to our visit to this area, Dr. van Schaik found wooden sticks in several Neesia fruits in this location – the first tangible evidence of similar tool use here. Because Tine and I hadn’t found tools five years ago in nearby swamp forests, this might indicate tool use in this area is very localized. On this day, we checked fruits on the ground and found two with tools in them.
Preserving a Paradise
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| Photo: Perry van Duijnhoven |
| Small fruit bats line the roof of a cave in West Batang Toru. Poachers are slowly but steadily depleting the bat population. |
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During the days we spent here we didn’t see any orangutans, but got a good feeling for the area and its unique features. One of these is a bat cave at the start of a river. Gabriella had heard it was somewhere in the area, but had not been there herself. Not really knowing what to expect we waded upstream through a river for about an hour. As we approached the cave, our wading turned into clambering over slippery rocks. Then as we climbed over a small hill we came upon a sight I will never forget. To our right was a gorgeous waterfall clattering down at least 300 feet and directly in front of us was a gigantic cave from which a stingy smell hit our senses.
As we slowly climbed into the cave and our eyes adjusted to the darkness, we lifted our binoculars to scan the dark walls. We all fell silent at the sight of millions of small fruit bats hanging in the cave. At the same time it also became clear that the smell was indeed from the bats – and we were standing in the middle of it! Sadly this amazing place is slowly being destroyed as the bats are harvested by people who hang wires with hooks in front of the cave in which the bats get caught and then are killed as food and medicine. As this process continues the cave is slowly but steadily being depleted. It is therefore not only for the orangutans that this area needs to be protected but also for smaller mammals like bats. This will not be an easy task.
But signs from the past gave me hope that change is possible. On our way to the cave, Iman one of the local assistants, pointed out a small mud wall in the forest. The wall, he explained to us, was the remains of a perimeter of an ancient living ground of a king. Where there was now a beautiful forest there had once been a village with a king. Where there was now a forest there were once the fruit trees that the villagers had planted – several domesticated tree species bear witness of that fact. Where there was once a village there were now orangutan nests. Although the causes of the disappearance of this village remain unknown it indicates that changes can go either way. Perhaps the logging concession, which makes up the southeastern part of the Batang Toru forests will one day grow back to almost primary forest. It can still go either way for the forest and its inhabitants and I have good hope that the current conservation efforts in the area will succeed.
Great Ape Trust Background
When completed, Great Ape Trust will be the largest great ape facility in North America and one of the first worldwide to include all four types of great ape – bonobos, chimpanzees, gorillas and orangutans – for noninvasive interdisciplinary studies of their cognitive and communicative capabilities.
Great Ape Trust is dedicated to providing sanctuary and an honorable life for great apes, studying the intelligence of great apes, advancing conservation of great apes and providing unique educational experiences about great apes. Great Ape Trust of Iowa is a 501(c) 3 not-for-profit organization and is certified by the American Zoo and Aquarium Association (AZA). |
Great Ape Trust is certified by the Association of Zoos & Aquariums
