Orangutans in the wild are using tools.

In 1994, Carel van Schaik of Duke University became the first anthropologist to document the use of tools among wild orangutans. His study investigated orangutans in the swampy Gunung Leuser National Park, in the northwest corner of Sumatra, who were developing implements to help themselves eat. Here, ravines, knee-deep water, and fish leeches keep out loggers, leaving the orangutans relatively undisturbed.

The swamp is densely packed with orangutans that van Schaik describes as gregarious and extremely tolerant of each other — an unusual arrangement for these apes, who are usually solitary. “The reason that tolerance is important is that we assume that the critical factor for using tools is the ability to learn it from others,” van Schaik explains. “Everybody is using tools, and everybody has the chance to observe it, so it is a social behavior.” Orangutans in captivity often use tools, but no one before van Schaik had observed this behavior in wild populations. Wild orangutans on the nearby island of Borneo have not developed tool use, perhaps because they are more sparsely distributed throughout the forest.

Living high in the trees of the flooded Gunung Leuser forest, orangutans locate pulpy fruits, of which their favorite is locally called “puwin.” Inside this fruit lies a rich source of protein and lipids; outside are tiny hairs that van Schaik describes from experience as feeling like “Plexiglas needles,” capable of delivering a painful jab. By sliding a thin stick into a crack in the fruit, orangutans can get the seeds out without having to handle the prickly husk. “Here is an example of how technology makes it possible for animals to make a much better living,” says van Schaik.

From an anthropological viewpoint, a phenomenon such as tool use represents orangutan culture, since the entire group participates in a behavior that has developed over time. This, in turn, may relate to the evolution of human cultures. For this reason alone, van Schaik believes these highly intelligent primates deserve protection from the threats of the illegal pet trade and habitat destruction. “Say the orangutan population is reduced, or goes extinct,” speculates van Schaik. “Then this behavior will die out. You can reintroduce orangutans into the wild, but not a culture.”

Like other primates, orangutans exhibit humanlike qualities — from careful parenting to the use of tools. But how do their thought processes work? Are orangutans capable of cognitively figuring out complex problems? To find out, Washington DC’s National Zoo has set up the Think Tank, a research center where orangutans do everything from solve puzzles to operate computers — tasks usually left to scientists. Rob Shumaker coordinates the Think Tank’s Orangutan Language Project, featured on the NATURE program. There, he teaches orangutans a language based on symbols to find out how they think.

Once the orangutans have learned how the symbols work, scientists reason, the apes may start to put them in an order that signifies meaning.

Azy, an adult male, knows seven different symbols. Shumaker and his colleagues also investigate how well these apes resolve complicated problems, such as retrieving food from locked containers.

Azy and Indah, a female also featured on NATURE, must figure out the best way to get a delicious-smelling peach out from a box shut tight with a variety of clasps. After some initial pummeling, both orangutans stopped bashing the boxes and used their hands, feet, and prior experience to get the clasps open, reasoning out the solution the same way humans do.

At most, 20,000 orangutans still exist in the wild, which is 30 to 50 percent fewer than were estimated 10 years ago. Once ranging throughout Southeast Asia, the species now occupies only small pockets of habitat on the Southeast Asian islands of Borneo and Sumatra. While their future is tied to their habitat, putting their fate primarily in the hands of the Indonesian and Malaysian people whose land they share, it also depends on the global economics that drive the timber market, as well as the worldwide market for illegal pets.

Orangutans are not stay-at-home animals. Every day, they travel through large areas of forest, gathering the variety of bark, insects, and different types of fruit they eat, which are spread throughout thousands of forest acres. But increasingly, the orangutan has had to compete for space with the logging industry. Timber is being harvested out of the orangutan’s habitat, stripping the forests. And most recently, a series of forest fires has devastated the area, causing untold damage to the already fragile habitat.

In addition to suffering the effects of logging practices, the orangutan’s habitat has fallen victim to agricultural development. In Malaysia, palm oil plantations have taken the place of forests, and one plantation can occupy as many as 50,000 acres. As forests are cleared for planting, orangutans’ homes shrink to small clusters of trees on which they are marooned, living in and eating from the trees that are farmers’ livelihoods.

Palm hearts make a delicious meal for an orangutan, who can easily go through 100 or more plants in a single evening. After unsuccessfull attempts to deter the animals by setting out scarecrows and building fences, plantation owners have sometimes resorted to killing the orangutans.

On the island of Borneo, farmers in the Malaysian state of Sabah have the option of capturing orangutans they find and bringing them to the Sepilok Orangutan Sanctuary, run by the Sabah Wildlife Department. This facility provides medical care for orphaned and confiscated orangutans, as well as for dozens of other wildlife species. The center also puts wildlife on exhibit for the public as part of an education program. Much like the orangutans at the Wanariset Orangutan Reintroduction Center, the rescue organization in Kalimantan, Borneo, featured on the NATURE program, the animals at Sepilok range from newborns to adults.

Many orangutans are victims of the illegal pet trade, which skyrocketed in the 1980s after a 1986 television show in Taiwan featured a family with an orangutan as a pet. Demand grew quickly, and poachers descended on the rainforests to grab baby orangutans and sell them on the black market. Taiwan is still the biggest illegal importer of baby orangutans. Once these babies mature, however, they become too strong and bossy for their owners, many of whom abandon them.

Even if these abandoned orangutans make it to the safety of a rehabilitative center like Sepilok or Wanariset, great damage has been done: in the process of taking a baby orangutan from the wild, hunters invariably kill the mother, leaving one fewer reproductive female. While a rescued baby may eventually return to the wild, it will be years before he or she will have offspring.

The work at Wanariset to reintroduce orangutans into the wild, as you see on NATURE, is making some headway in counteracting the combined threat of deforestation and kidnapping.

But first, the workers there must spend a lot of time teaching the resident apes how to survive in the wild: kidnapped before they can absorb the crucial lessons of life from their mothers, many of these animals have no idea how to perform basic skills like climbing, swinging, or harvesting fruit. As long as the animals reintroduced into the wild are disease-free and can fend for themselves, there is a chance that they will produce a new generation of wild-born offspring.

If you are interested in learning more about Wanariset and the work they do, visit their Web site, where it is possible to help the cause by sponsoring an individual orangutan and watching its progress from halfway around the world via the Internet.

That’s not surprising when you think about how closely related we really are. The only primate closer to us is the African ape. But as human as they seem, orangutans are actually wild animals perfectly suited to their forest environment. Weighing in at a hefty 200 pounds, an adult male orangutan is four times as strong as an adult male human and the largest animal to dwell in trees. When climbing on vines, orangutans’ flexible hip joints and hand-like feet make them seem to have four arms rather than two arms and two legs.

The natural home of the orangutan is the leafy canopy of the Southeast Asian rainforests in Sumatra and Borneo, which are abundant with the fruit that these apes eat. The growth of the logging industry in these areas has placed this habitat in grave danger, so many zoos have begun programs to increase the worldwide orangutan population.

Whether they live in treetops or zoos, orangutans exhibit a high level of intelligence. Orangutans in the wild are capable of creating and using tools; those in captivity demonstrate their ability to think and solve problems, like the puzzles at Washington DC’s National Zoo, featured in rangutans: Just Hangin’ On. It is no accident that the Malay name for this animal, “orang utan,” translates as “man of the forest.”

Online content for Orangutans: Just Hangin’ On was originally posted December 1997.