"It's nighttime in the rainforest, and when Mama tells young Faly to shut his eyes, he objects. "Only if Mahandry sleeps, too," he tells his mother. "But I am bigger than you, Faly," answers the older lemur brother. "I am allowed to go to bed later." Thus begins a spirited back-and-forth and a family gambol that brings a mama and her two lemur sons from the hollow of their tree to a dangerous wide river crossing to a slippery rushing waterfall and...