It’s feeding time at the Myakka City Lemur Reserve, a leafy 90 acres about 25 miles east of Sarasota, Florida. On this steamy morning in early March, baskets containing pellets of monkey chow, fruit, and other treats drop from the trees onto a clearing. Three ferretlike brown lemurs, the pint-size alpha dogs of the preserve, make a beeline for the food. They elbow aside their less aggressive—and slightly affronted—brethren: the red-ruffed lemurs, sporting stiff Elizabethan collars of fur, and the hypervigilant ring-tailed lemurs, whose facial markings and luxurious striped tails give the impression of svelte raccoons.
Yale University psychologist Laurie Santos squats on the ground surrounded by half a dozen of these curious primates. They regard her quizzically while she takes pictures of them with a digital camera. The photos aren’t keepsakes of her field trip but will be used to help her comprehend the social structure of lemurs, specifically whether they have an affinity for forming social cliques.
Lemurs, from the island of Madagascar off the coast of Africa, evolved in isolation for some 30 million years. Despite this long separation from the rest of the primates, they now have something in common with a group of rhesus macaques in Puerto Rico and capuchin monkeys living at Yale: They all contribute to Santos’s wide-ranging study of our primate relatives, offering an unparalleled glimpse into our evolutionary past. Monkeys, it turns out, have many of the same survival skills that we do, from a predilection for forming groups to a knack for taking risks and deceiving adversaries.
Santos’s studies show that monkeys also possess many of the quirks and foibles once considered uniquely human. Like us, they intuit what others are thinking by reading social cues, a skill that may be millions of years old, hardwired into the primate brain. They make the same errors in economic reasoning that we do, suggesting our sometimes irrational attitude toward money might once have conferred an evolutionary edge. Through a series of groundbreaking experiments, Santos has seen in her primates a humanlike propensity for hoarding, larceny, and competitiveness. By exploring the inner lives of primates, she has offered persuasive evidence that monkeys are capable of sophisticated insight, complex reasoning, and calculated action.
Although the 33-year-old New Bedford, Massachusetts, native grew up surrounded by cats and dogs—her mother is a pet rescuer —Santos originally aimed for a career in law. The switch to studying animal behavior was, she says, “utterly serendipitous.” Shut out of a prelaw seminar in her freshman year at Harvard, she took a psychology class that ultimately led her to the study of nonhuman primates. She was captivated. Now an associate professor at Yale and head of the university’s Comparative Cognition Laboratory, Santos explains to DISCOVER how she learned to think like a monkey—and, in the process, came to understand more about how humans think too.
