"Have I been pissed on? Yes," says anthropologist Cheryl Knott of Harvard University. Knott is a pioneer of "noninvasive monitoring of steroids through urine sampling." Translation: Look out below! For the past 11 years, Knott and her colleagues have trekked into Gunung Palung National Park in Borneo, Indonesia, in search of the endangered primates. Once a subject is spotted, they deploy plastic sheets like a firemen's rescue trampoline and wait for the tree-swinging apes to go see a man about a mule. For more pee-catching precision, they attach bags to poles and follow beneath the animals. "It's kind of gross when you get hit, but this is the best way to figure out what's going on in their bodies," Knott says.