Biological anthropologist Cheryl Knott wonders if the orangutans she studies deep in Borneo's rain forest are destined to vanish from the wild forever. With more than 80 percent of their habitat lost and illegal logging expanding at an ever increasing pace, preservation efforts have become as important as research.

"Because orangutans spend 99 percent of their time in the trees, deforestation has devastating effects on their ability to survive," Knott explains. "They eat, sleep, nest, and travel in the rain forest's leafy branches, totally dependent upon the fruits, leaves, seeds, bark, and insects the trees provide. And since orangutans only bear young about once every eight years, they can't replace their numbers fast enough."

That eight-year interval may be the longest reproductive hiatus of any mammal. Knott has sought to explain why it occurs. In field studies measuring hormones in orangutans, she has discovered significant links between reproduction fluctuations and the availability of fruit.

Today Knott's research not only furthers our understanding of these endangered great apes, one of humankind's closest living relatives, but provides clues to our own evolutionary history.

"My ultimate goal is to understand how the environment influences orangutan biology, especially how we can use that as a model for looking at human evolution," says Knott, who earned an undergraduate degree in anthropology from the University of California, Davis, and a Ph.D. in anthropology from Harvard University, where she now serves as an associate professor of anthropology.

"I've always been interested in the questions evolution raises. I'm driven to understand both the similarities and differences between humans and the great apes," Knott says. "For example, studying cultural traditions in orangutans really makes me think about how similar we are in many ways. Have some of our own traditions existed at a deeper level for a long time, first in the apes and then in humans? What other aspects are truly unique to humans? And how did the things that are different between us and the apes evolve?"

Knott conducts her fieldwork in Borneo's Gunung Palung National Park, home to 2,500 orangutans and her ten-year study. "This is the last—really, only—long-term research site for orangutans in the world," she notes.

Her far-reaching commitment to protecting the park includes an integrated strategy of supporting rain forest ranger patrols, working with government decision-makers, developing community awareness campaigns, raising local pride in the park, and providing environmental education. But even in this once unmolested wilderness, loggers have arrived.

"We make our home in a house built on stilts next to a river you can bathe, swim, and drink from," Knott says, describing her life in the field. "The noises are just incredible—birds calling through the thick, humid air. But of course now we can also hear chain saws."

As trees fall and the orangutans' habitat shrinks, every new piece of information Knott gleans about the declining species can be crucial. "For me," she says, "the bigger picture is understanding how what we learn about orangutans can help us to better understand ourselves."