Sanz hands us each a surgical mask—to protect the chimp, not us. "Talk about maladaptive behavior," Morgan whispers, with a chuckle. We back off a bit and spend the next several hours with our ...

An hour’s drive down a ragged dirt road, deep in the heart of Uganda’s Kibale National Park, a small research camp sits in the middle of chimpanzee territory. Tangled vines drape ancient trees ...

Only identified as a species separate from chimps in 1929, bonobos intrigue biologists with their easygoing ways, sexual equality, female bonding, and zeal for recreational sex. How did bonobos ...