* Some readers might balk at this statement, rightly pointing out that squirrels, scrub jays, and many other species cache food and otherwise prepare for the future. In none of these animals, however, is there any evidence that they actually understand their future needs. Rather, they appear to have evolved caching as an instinctive behavior in the absence of foresight, without any understanding of why they behave as they do (in much the same way that female chimps evolved to leave their birth group to avoid inbreeding). These issues are discussed in detail in Thomas Suddendorf’s excellent book, The Gap.