 HBEs, like behavioral ecologists studying non-human animals, tend to use optimality modeling to find strategy descriptions and sets of plausible selection conditions that make sense of observed patterns of behavior as locally optimal adaptations, and the reasoning works in much the same way. However, there are a few differences, most notably in how models are chosen. In cases where the structure of the problem might be unique to the human case and where the current environment is expected to be different from the situation under which the strategy originally evolved, the model HBEs choose will often be unique and at least some of the proposed selection conditions identified by appealing to information about the fossil record. A nice example might be human life history, where the human situation is relatively unique: for example, compared to other primates humans have unusually long lives and childhoods, and long life after menopause. As a consequence, the human behavioral ecologists have to appeal to the fossil record in detail to determine what sorts of evolutionary transitions might have been involved (Hawkes, 2003; Kaplan et al., 2000). Where the structure of the adaptive problem humans face and the conditions acting on their behavior is expected to mirror those in non-human animals and to be very similar to those humans encountered in their evolutionary past, the choice of model is often a standard one from non-human behavioral ecology; the proposed selection conditions can be based on the current conditions observed in foraging societies. In the Ache foraging case, this is exactly what happens: the prey choice models used by Kaplan and Hill are those used to understand similar sorts of strategies in non-human animals. This is because Kaplan and Hill expect the relevant conditions acting on human prey choice—such as profitabilities and search times—to mirror very closely those acting on non-human animals.