“In college, I worked with chimps using sign language,” Jenna said. “It took months to teach them a simple gesture. But watch this.” She held up one hand, her fingers moving quickly through the American Sign Language alphabet. As soon as she stopped, the monkeys imitated her—all twenty-six letters. “So what are you concluding?” Nick asked in a hushed voice. Maybe the monkeys could hear him. Maybe they could read his mind. “That they’re more intelligent than humans?” “I wish that were all.” Jenna’s voice lowered. “The thing is, this is a one-way polycarbonate observational window. The other side is mirrored.”