The sign at Camp Leakey on the Indonesian island of Borneo says: “Never stand between a male and a female orangutan.”
We were watching a group of female orangutans feasting on bananas, babies clinging to their bellies, when we learned why.
First came the sound of snapping branches, like a bulldozer crashing through the forest. The mother orangutans stuffed their mouths with bananas and started to flee just as Tom, a massive red-haired ape with black cheek pads framing his glassy brown eyes, swung down from the trees.
One female, Akmad, was too slow to escape the long arm of Tom. He grabbed her ankle, tossed her on her back and had his way in less than a minute. When Tom was finished, he let out a loud fart.
My wife and I visited Borneo in November, taking a four-day river trip to see some of our closest relatives on the evolutionary tree in their native habitat. We have gone on safaris to view tortoises in the Galapagos Islands, wild tigers in India’s Ranthambore National Park and grizzly bears in Alaska’s Denali National Park. The Borneo trip was my favorite.
“Orangutan” is an Indonesian word for “jungle person.” The babies are cute. The youthful apes are naughty. The mothers are nurturing. And you don’t want to get in the way of the dominant males.
We were the only passengers on the Kosasi, a 40-foot (12- meter) wooden boat powered by a single-cylinder diesel engine. It putted lazily up the Sekonyer River, gateway to the Tanjung Puting National Park, a refuge for one of the world’s largest colonies of the rare apes.
Orangutans are native only to the islands of Borneo and Sumatra, their habitats shrinking from encroachment by loggers and palm-oil plantations, their ranks decimated by poachers and trappers. The Sumatran orangutan population has dwindled to an estimated 7,500, according to the World Wildlife Fund, which lists the species as “critically endangered” with the possibility of extinction in 50 years.
An estimated 41,000 orangutans live in Borneo, according to the WWF, including about 38,000 in Indonesia’s Central Kalimantan province, where the Tanjung Puting park is.
Research on Borneo’s orangutans has been conducted continuously since 1971, when a then-graduate student named Birute Galdikas persuaded Louis Leakey, the famed African paleontologist, to fund her studies in Tanjung Puting.
Galdikas became one of “Leakey’s Angels,” living among Borneo’s orangutans as Jane Goodall stayed with the chimpanzees of Tanzania and Dian Fossey dwelled among Rwanda’s mountain gorillas. Galdikas still supervises research in Tanjung Puting, financed in part by the Orangutan Foundation International, a Los Angeles-based not-for-profit group she co-founded.
She established Camp Leakey as a center where orphaned and domesticated orangutans are rehabilitated to survive in the wild. The first chapter of Galdikas’s autobiography, “Reflections of Eden: My Years With the Orangutans of Borneo,” is titled “Akmad” after the ape who couldn’t escape Tom.
“Akmad was a lady,” Galdikas writes. “How human she appeared, like an orange gnome, with her intelligent, quietly inquisitive face.”
Loggers captured the infant Akmad shortly after Galdikas arrived in Borneo, according to “Reflections,” holding the ape in a cage for possible sale until she was rescued and transferred to Camp Leakey for “rehabilitation.” Orangutan rehab consists mostly of daily feedings to help the apes survive while they re-adjust to life in the wild.
Orangutans are usually reclusive, but those in rehab can be naughty neighbors. Rangers shield the windows of their cabins and outbuildings with chain-link fencing to prevent intrusions. During our visit, one ranger briefly left his kitchen door ajar and a female orangutan named Tutut dashed inside. She emerged with a bottle of hot sauce in her mouth and the ranger in pursuit. The ranger coaxed Tutut, who happens to be the mother of Tom, to exchange the hot sauce for a banana.
Deeper in the jungle, the apes converged on wooden platforms to enjoy their daily servings of bananas. Wild pigs and squirrels also joined the feedings.
The orangutans swung from tree to tree, using their weight to bend branches until the next limb came into reach of their lanky arms. Their wingspan can grow to as much as eight feet. They scampered over trunks and vines, stuffed their mouths with fruit and clambered away.
The females are said to be at least four times as strong as a human. The males, like Tom, weigh as much as 300 pounds (136 kilograms) and have eight times the strength of a human.
We took a prop plane from Surabaya, Java, to Pangkalanbun in Central Kalimantan, then rode an SUV for a half-hour to the port of Kumai, where stevedores shouldered bags of rice onto riverboats that carried cargo deep into Borneo’s jungles.
We boarded the Kosasi and crossed a broad bay, entering the mouth of the Sekonyer River in the late afternoon, passing a billboard with a picture of Tom, welcoming us to his kingdom. It said his reign as dominant male began in 2006, when he dethroned a predecessor.
As the sun sank, the cloudy sky turned pink and the wildlife came out. A hornbill that looked like a toucan, a stork-billed kingfisher and a huge bat called a flying fox soared above us. Proboscis monkeys with pink hooked noses chattered like a quarreling family as they clambered through trees. A monitor lizard dozed on a branch.
Darkness fell. From palm trees that lined the banks, a firefly drifted onto the boat. Soon, the fireflies came in clouds, swarming and swirling like silent fireworks. We were beyond the range of our mobile phones. The only mechanical sound was our putting boat, which fell silent after the crew lashed it to the side of the river and we settled in for the night.
Shielded by a tent of mosquito netting, we slept on mattresses rolled onto the deck. On the river, it was cool enough to doze comfortably without air conditioning, even though Tanjung Puting is only about 3 degrees latitude south of the equator.
We awoke at dawn to the jungle din -- droning cicadas, chirping frogs, warbling birds, blabbering macaque monkeys.
More than 40 wooden boats such as the Kosasi ply the Sekonyer River, ferrying tourists to the feeding stations for three- and four-day trips. Speedboats also roar out of Kumai to make the Camp Leakey journey in a single day.
August and September make up the peak visitor season, when the tropical rains let up. More than 100 tourists at a time troop to the feeding platforms, their prattling scaring away many of the apes, according to our guide Kres Harytono, who spoke fluent English and a little Spanish. During our November trip, we never saw more than three other tourists at a time.
The three feeding stations we visited were about a half- hour walk from the river. Orangutans came to greet us on the path. We fed bananas to one named Rica and her baby Roy. After Rica sucked the fruit down, she returned the empty peel to Kres or handed it to Roy.
“I like Rica,” Kres said. “She’s beautiful.”
Akmad was also beautiful, Galdikas wrote, and mysterious. The ape would stay away from the camp for years as she raised her babies in the wild. She would return at odd intervals, occasionally climbing into the scientist’s bed for comfort, like a member of the family.
Tips: Citizens from 63 countries, including the U.S. and European Union, can obtain 30-day tourist visas on arrival in Indonesia. We booked a four-day/three-night trip to Central Kalimantan, including round-trip airfare from Java, via Wisata Alam Indonesia Tour Services, http://www.oranghutantour.com. It cost $700 per person. The package covered food, non-alcoholic beverages, on-board sleeping accommodations and an English- speaking guide. We tipped the guide and boat crew after our trip. The dry season from about June to October offers the best weather for visits but can also be crowded. More information on orangutans is available through the Orangutan Foundation International, http://www.orangutan.org.
(John Gittelsohn is a reporter for Bloomberg News. The opinions expressed are his own.)