Whistling for Honey

How old is the human sweet tooth, and why do we crave sweet things?

As it happens, these two questions will take us far from our distant ancestors and their hunger for wild honey. They will lead us to still other questions, questions that have to do with the emotions the natural world arouses in us—yearning and revulsion, joy and fear—and how those emotions have shaped every aspect of our lives.

But our story starts here, following a prehistoric hunter somewhere in Africa, whistling for honey.

Until humans figured out how to refine sugar from plants such as sugarcane and sugar beets, we had to steal from creatures skilled at concentrating the nectar of flowers into a rich source of food: honeybees. Our ancestors learned how to rob the nests of wild bees at least twenty thousand years ago—rock art of that age survives in Zimbabwe (figure 1.1) The image left behind on the rock face clearly shows a person smoking a hive to get honey.

Our African ancestors must have found honey a sweet temptation: it was nutritious, delicious, and easy to digest. But bee colonies are uncommon on the African savanna. In order to find and exploit them, prehistoric humans relied on an unusual partner that also benefited by leading them to the hives. That partnership has persisted into modern times; we can still witness it today in several African tribes, among them the Boran of northeast Kenya.

Just before setting off in search of honey, Boran honey hunters give a specific, loud whistle, known as the fuulido (figure 1.2). If they're in luck, there will be a return call from a bird with a fuulido of its own. The caller is a greater honeyguide, a small bird; its Latin name, Indicator indicator, reflects its value to humans. The honeyguide repeats its distinctive "follow me" call, and begins to escort the Boran hunters to a bee's nest, pausing frequently to allow the hunters to catch up. Most astonishing, upon arriving at the tree where the bees have nested, the honeyguide perches and sings a special "indication" song. The bird escort remains nearby as the hunters disperse the bees and claim the prize of the honeycomb. In gratitude, they always reward their navigator by leaving behind some honeycomb. Unlike most birds, honeyguides can digest wax; they feast on it along with the honey and bee larvae lodged in the comb, but honeyguides are too small and weak to open bees nests. They depend on humans to do it for them, just as people depend on honeyguides to help them find the nests.

This unusual mutually beneficial partnership features in the myths of many African savanna-dwelling tribes. Our ancestors probably gorged on honey whenever they could find it. Honey was a nutritional and energy bonanza, a precious fuel for our large hominid brains. But the rarity of hives in the savannas made it impossible to gather enough to grow fat on this rich resource.

By contrast, walk the aisles of a modern supermarket and count the staggering variety of sweet and sugary foods. We modern humans are blessed and cursed by uninterrupted access to sweets, and we have become slaves to our sweet tooth. Hardwired with our ancestors' cravings for sugar-rich foods, we're unable to resist. We are also adapted to an environment where food was sometimes abundant and sometimes scarce. When it is abundant, we lay on fat for the future hard times. Today, hard times rarely come. As a result, obesity is now a serious health problem throughout the developed world and an increasing problem in developing nations.

It turns out that a fondness for sugar is just one trait our ancestors bequeathed to us. Our ancestors' responses to environmental challenges—unpredictable sources of food, ever-present predators, extremes of weather—have molded our modern emotional lives. They are a central theme of this book. Evolutionary psychologists tell us that whenever we're incited to act by strong emotions, positive or negative, chances are good those actions were of great evolutionary importance. Responding appropriately to stimuli meant the difference between surviving or not, leaving offspring or not.

Our ancestors came to prefer or "like" beneficial objects and events in nature that increased their chance of surviving and passing on their genes to their children—in short, evolution by natural selection. Conversely, they came to avoid or "dislike" objects and events that were threatening and decreased their chances of surviving and reproducing. Over time, these likes and dislikes became wired in the human brain. As a result, we have a taste for honey and a nearly universal fear of carnivores with big teeth. Science allows us to trace these ancient emotions and find the adaptation in what we find beautiful and what fills us with revulsion and fear. We can better understand how we interact emotionally with our environment by viewing our behavior through an evolutionary lens that focuses on our ancestors.

This book records the results of my efforts to find out how our emotional lives bear the imprint of decisions our ancestors made long ago on the African savanna as they selected places to live, sought food and safety, and socialized in small hunter-gatherer groups. I hope to convince you that the impressions are many and deep and the rewards for this new understanding as useful as the honeyguides are to the Boran people.

How I Came to These Questions

My search for an environmental basis to emotions and aesthetics began the year I was seven, when I discovered the world of birds. My family rented a cabin on a lake in northern Wisconsin, and I was captivated by the call of the common loon. I soon began to record observations of birds I saw; those notebooks still sit on the shelves of my university office. When I was about thirteen, I joined birders in the Milwaukee, Wisconsin chapter of the Audubon Society. A few of them were professional ornithologists. At some moment, I put two and two together—people were actually paid to study birds! I decided then that I would go to college, major in biology, and become a professional biologist. I did exactly that. I became a behavioral ecologist because I was interested in the decisions birds like honeyguides must make to be successful—how they select habitats, search for food and decide what to eat, chose their mates, and invest in their offspring.

In my young adulthood I never questioned my strong attraction to birds. I simply enjoyed them. But as I matured as an evolutionary biologist, I began to think deeply about human emotional responses to nature. My thoughts, as well as those of many other people, were stimulated by Edward O. Wilson's Sociobiology: The New Synthesis, published in 1975. Wilson helped me recognize that the decisions...