National Geographic : 1998 Aug
Field Data When the apes turn in early, our open stilt house (above) provides a retreat to review the day's data. At dawn I am back on the forest floor, collecting urine (left) from an orangutan just awakening in her nest above. I can test the urine on site for signs of menstruation, infection, and weight loss (bottom left). I save some samples for later genetic analysis, so I can learn who is fathering off spring and how the animals are related. I'll also analyze the hormones in the urine back at the lab. By measuring hormones for the first time in wild orangutans, I've found that estrogen levels increase when nutritional status improves. Pregnant Beth (right) con ceived her baby Bekti during the mast fruiting, when estrogen levels were high.