Humans Find Chimp Eden
Most primates have good reason to fear humans, since the naked ape has a long history of hunting or poaching them or clear-cutting their habitats. But a study published in April offers a glimpse of an extreme rarity in the modern world: chimpanzees that have had little or no previous contact with people. Dave Morgan, a field researcher with the Wildlife Conservation Society, and Crickette Sanz, a doctoral candidate in anthropology at Washington University in St. Louis, encountered the chimps in an all-but-impenetrable forest in the northern Republic of the Congo—a 100-square-mile area called the Goualougo Triangle. “There were large groups coming forward, circling us, calling others,” says Sanz. “You could see their curiosity. I couldn’t believe it.”
Between February 1999 and June 2001, Morgan and Sanz spent a total of 365 hours observing the chimpanzees. “We could sit with these chimps for as much as seven hours,” says Sanz. Eventually the chimps forgot about the scientists and resumed their usual routine—eating fruit, lounging in their day nests, grooming each other, and mating. “What’s so important here is that nearly all other chimpanzee study sites have been disturbed in a major way, mucked about by humans,” says anthropologist Robert Sussman, Sanz’s doctoral supervisor.
Morgan and Sanz documented more than 20 “cultural variations,” or behaviors not seen in other chimp populations. “There is very little violence, no infanticide, none of the territorial fighting seen with other populations,” Sussman says. “Here we have a baseline that we could watch for 20 years and see for the first time what really normal behavior is for chimpanzees.”
—Michael W. Robbins
Orangutans Show Signs of Cultured Behavior
An orangutan that emits a loud raspberrylike noise before turning in for the night has culture. That’s one of the surprising findings of nine primatologists who announced last January that orangutans are multicultural creatures. In other words, invented behavior patterns are passed on from one generation of orangutans to the next and often vary from one group to another. Researchers thought culturally transmitted behavior was limited to humans and chimpanzees, but the new study suggests that all great apes share a common ancestor that was multicultural.
Drawing on extensive fieldwork conducted at six different locations in Borneo and Sumatra, Carel van Schaik of Duke University and his colleagues examined 36 behaviors performed by orangutans. They discovered that 19 behaviors, such as using a fist to amplify sound or using a tool held in the mouth to poke a hole in a tree and pull out chunks of termite nests, ants, or honey for a snack, appeared at some sites but not at others, and there was no ecological reason to account for these differences. Orangutans’ new status as cultural animals was unexpected because typically they are less social than chimps and so, researchers believed, they would have fewer chances to learn from one another.
The ultimate implication of the research is that humans still have a lot to learn from other primates. “Wild apes are our outdoor lab for the evolution of human culture,” says Van Schaik. “Preventing habitat destruction becomes even more desperately important now because we need not just one group, but many, to understand how humans became so cultural.”
—Meredith F. Small
Baboon Surprise: Father Knows Best
Free love is the norm for the wild savanna baboons near the foot of Mount Kilimanjaro in Kenya. Males and females alike are unabashedly promiscuous. The females are doting mothers, but scientists who observed the baboons for three decades weren’t sure whether the males even recognized their own progeny. It turns out that they do. In September a team led by Jason Buchan, a molecular behavioral ecologist at Duke University, produced genetic evidence that male baboons are caring dads.
During a three-year-long field study, Buchan and his colleagues focused on instances when an adult male intervened to protect an individual juvenile who was threatened or bullied. The researchers initially assumed that the male was trying to impress the juvenile’s mother. After analyzing DNA from fecal samples, they matched up 75 juveniles with their fathers and were surprised to discover that male baboons not only recognize but also clearly favor their own genetic offspring. Exactly how baboon fathers manage to identify their offspring remains a mystery, but Buchan’s team hypothesizes that pheromones and odor molecules probably play a role.