Sumatran orangutans study for nature's pass/perish entrance exam

The best students are the wildest. Lesson 1: Avoid humans at all costs.

I'm struggling to make friends here. Miriam, a 9-month-old orangutan orphan who's learning how to climb a tree, almost scales past her trainer when I approach. For good measure, she starts to cry. Another orangutan signals displeasure by emulating the sound of a Harley barreling toward me. In fact, the only one who tolerates me is 11-year-old Leuser, and not because the 42 air-rifle pellets lodged in his body have mellowed him. He's also blind.

At any zoo, these surly apes would bomb the aw-isn't-he-cute exam, but here at the world's most successful school for rescued orangutans, they're taught to get back in touch with their wild side. Even playtime is serious business. Passing, say, the test of recognizing a friend (another orangutan) versus a foe (a human logger) could spell life or death for these critically endangered icons of the old world jungle.

Everything happens here with one goal in mind: graduation day, when the shaggy students are set loose into the harsh Sumatran rain forest. But for the students to have a shot at survival, handlers must teach them to avoid humans at all costs, a tough task considering they need to be fed by humans.

"We need to take care of these confiscated animals and return them to the wild," says Ian Singleton, director of the Sumatran Orangutan Conservation Programme. "But we need to do it scientifically."

And real science doesn't involve a line of gawky tourists dangling bananas and posing for pictures. That's why this center at the far north of Sumatra – one of the main islands of Indonesia – is closed to the public and barely known to outsiders. Even if you made it to the nearby village of Batu Mbelin – where the specialty dish is fruit-bat soup and the humid air is clouded with mosquitoes, this part of Sumatra – is definitely not for the faint of heart.

I reflexively clench the door handle of Mr. Singleton's SUV as we cross over a rushing river on a wooden bridge. Palm trees line the one-lane road to this village, and in the distance, various plantations – chocolate, banana, papaya – dot the endless green of the hills.

"Kai berita," Singleton shouts in the local Karo Batak tongue to villagers we pass. He turns to explain, "I hate to be that white guy who drives by with the windows up and air-conditioning on."

With the locals, many of whom work at the rehab center, he's gained the reputation as a man unusually obsessed with orangutans, which are found only in the lowland forests of northern Sumatra and the nearby island of Borneo. They don't understand, at least initially, why he would offer the apes a hollowed-out block of wood with honey inside to play with, rather than just chicken and rice, the customary diet of pet orangutans. Turns out, it's a useful skill for wild orangutans to learn how to scrape honey out of a tree hole.

"The handlers come here thinking an animal is an animal, that as long as you feed them, they're fine," Singleton says. "But they're not. They need behavioral enrichment." Another trick to keep the students sharp is to tie up rice sacks with the food inside (they like any sweet fruit). "Some of them rip it open," he says. "But the smart ones untie the bag."

But you could say those are elective classes. Most of the orangutans come here either completely spoiled by their former owners – almost all military officers who keep them as illegal pets – or with injuries from clashes with farmers and illegal loggers. The injured receive medical attention, and former pets are quarantined for a few weeks and then transferred into a sprawling system of socialization cages. For the young ones, it may be the first time they've seen another of their kind. "Sometimes they don't have a clue how to take care of themselves," says Singleton.

The night before this jaunt, Singleton was up until 2 a.m. discussing X-rays with a Swiss surgeon who flies here for emergency surgeries.

During the socialization stage, the residents make friends – and sometimes enemies. Two 30-pound toddlers, Kevin and Irwin, are rolling around some blue oil drums when they decide to fight (it looks more like tickling). Just as quickly, they become bored and begin swinging from ropes attached to the ceiling of their metal cage. The playground bully, Prince, who's bigger by at least 25 pounds, glares at them, ready to steal their milk when the handlers bring the twice-daily bowls.

Though wild orangutans are usually solitary animals, a landmark 2003 Duke University study revealed that they have culture, the only primates besides chimps with this human characteristic. Even more surprising, they've been observed using all sorts of tools to dig for termites, scrounge for honey, and get at the seeds inside the razor-sharp neesia fruit – knowledge passed from ape to ape. After all, it's unlikely a whole troupe of orangutans simultaneously realized leaves could double as gloves or umbrellas.

"Now we know how much these animals learn socially about basic forest skills," Carel van Schaik, an anthropologist at the University of Zurich and lead author of the Duke study, explains in a phone interview. "So you can imagine, if you take naive animals and stick them into the forest, that's going to be an enormous challenge. Ian is doing a very good job of preparing these animals."

If all goes well, the students will soon leave this garden paradise – with its freshwater springs, wood gazebos, and hanging orchids – for the tiger-infested rain forest of Jambi Province. It'll be a 36-hour drive down the spine of Sumatra to a place even more hidden than Batu Mbelin.

There, they must pass their final test. Handlers will bring them into the jungle each day and teach them everything else they need to survive: what fruits to eat and where to find them, how to eat ants and build nests, and perhaps how to use a tool or two. The wilder ones may graduate in a couple weeks. Tamer ones could take months or years. And the tamest ones? Well, like human students, they don't want to get out of bed until noon and will expect food to be handed to them on a plate (and don't even ask them to build a nest anywhere off the ground).

Regardless of their survival know-how, these orangutans face poor odds. Only 6,500 remain in Sumatra and 50,000 in Borneo, down by half from two decades ago.

"Surviving in the wild is not instinct. They have to learn an enormous amount," explains Rob Shumaker, an adviser to orangutan re-introduction programs in Borneo. "I know all the players, and what [Batu Mbelin] is doing is as good as it gets," he adds in a phone interview from the Great Ape Trust in Des Moines, Iowa, where he is the director of orangutan research.

Indeed it takes stellar teaching to assure an orangutan takes to the wild. More than 90 orangutans have been released since 2003, when the reintroduction began. And it's not goodbye after graduation. Field observation of the animals suggests the survival rate may be as high as 80 percent.

As it stands, wild orangutans need all the help they can get. At current rates of growth, illegal logging, mining, and oil palm plantations, could destroy 98 percent of the orangutan's habitat by 2022, a UN report warned last year. Many conservationists predict the extinction of the orangutan within a decade or two..

Before we drive back to town, Singleton takes me to a nearby abandoned botanical garden. By this fall, he plans to turn the place into an educational center for local schoolchildren to learn about orangutans and the rehab program. It's obvious he's an educator at heart. No wonder his hairy graduates are at the top of their class.