hile Winterhalder’s studies focus primarily on basic understanding, the work has a practical side, as well. For example, learning how people exploit their environment yields information that may be useful to those managing natural resources, he says. His mathematical models include simulations in which foragers make decisions about which prey or plants to harvest based on principles of foraging theory.

"We then use a computer to examine the impact of the decisions on the animal populations, their densities, and their ability to recover their numbers, and how changes in those densities affect the way people make their decisions about foraging," he says. "The results can yield information about which species are most vulnerable to localized extinction and why."

He points out that conservation biologists and game managers never have enough empirical data to make sound predictions. "Humans live a long time, and some of these game species live a long time," Winterhalder says. "The demographics of their interaction with each other play out over dozens of years or longer periods of time. For all of the generous funding of research in this country, nobody gets grants to study the same population for dozens of years in a row. It just doesn’t work that way. So what we’re trying to figure out is how we can help advance the understanding of those processes through behavioral ecology models and computer simulation. For instance, there are proposals from conservation biologists in places like Brazil to set up large reserves in which native people continue to have rights as managers and harvesters of game. Ethically, since these people are indigenous to those lands, that makes some sense. But we need to understand more about the populations and how they are using the game. For example, they have rifles rather than blowguns, now. What’s going to be the impact of a change like that?"

In fact, people in various fields are finding unexpected uses for foraging theory, Winterhalder says. Working at home on his family’s genealogy, Winterhalder typed his name into an online search and turned up a couple of papers by a group of software engineers who were applying his work to help them analyze how people look for information on the World Wide Web.

"If you had asked us ten years ago if someone was going to figure out how to apply foraging theory to internet software engineering, we would have said, ‘Are you kidding?’" Winterhalder says. "But here was a group who had done it."

n the web or in the wilds, individuals make choices as they forage, and these choices accumulate into trends that can drive a sector of the economy or determine the fate of an ecosystem, Winterhalder says. But for some social scientists, especially those who embrace the principle of human uniqueness, the ideas of human behavioral ecology are troubling. For years, Winterhalder and his colleagues have encountered people who felt that finding evolutionary or ecological explanations for human choices is to take a position in favor of biological determinism, to reduce the sublime complexities of human culture to the basics of biology.

But in Winterhalder’s view, there is nothing antisocial or demeaning in the notion that human beings have always been a part of Nature’s give and take. In a paper about the ecology of hunter-gatherers, he writes: "Behavioral ecologists acknowledge that hunter-gatherer behavior surely is complex and multi-causal in origin, but they also insist that until we know the effects of causes taken separately, there is little possibility of understanding their actions taken together." He adds, "We happen to be focusing on causes that have their bases in ecology and evolution, in part because they seem to be more predictable from theory."

So for Winterhalder and his students and colleagues in behavioral ecology, the hunt is on. They are ranging the planet and crunching the numbers, foraging for the evidence that will help us understand how we became who we are. And as they find that evidence, they will know what to do with it. They will bring it back to camp. And then they will share.