Attempts to identify New Guinea's hunter-gatherers face the well-known difficulty of defining what constitutes a hunter-gatherer group. According to the common definition, hunter-gatherers are those who subsist by hunting wild animals and gathering wild plants. Yet, those criteria beg numerous questions, including the issue of what constitutes "wild". The very presence on a landscape of humans who are consumers affects food resources, blurring the lines between wild and domesticated and, hence, between hunting and pastoralism and between gathering and cultivation. Moreover, it is unclear how groups should be classified that are hunter-gatherers in their procurement strategies but that make use of pastoralism and cultivation in their consumption patterns – subsisting, for example, by trading wild foods to neighbors in return for domesticated crops.