Twenty minutes southeast of Des Moines, Iowa, you’ll find a large, unassuming cement complex with fenced in grounds. You’d never know it, but inside are five bonobos—including the world-famous Kanzi—thought to be the only remaining nonhuman apes capable of communicating verbally with humans. We speak with Dr. Sue Savage-Rumbaugh about what she’s learned from and about bonobos, humankind’s gentle cousins, during an extraordinarily ambitious, 30-year investigation into their minds.