Carbon and nitrogen isotope analyses of human bone collagen can be used to determine sources of protein in the human diet. Here, we examined and summarize isotopic data from analyses of hunter-gatherer people living along the Pacific coasts of North and South America from 10,000 years before the present to about 100 years ago, using seven regions with archaeological sites ranging from Alaska to Tierra del Fuego. At sites throughout this region, we find that nearly all animal-derived protein in the diet derived from marine animals, either high trophic-level fish or mammals. In British Columbia, some also consumed high-trophic level freshwater fish. In California and Peru, a significant amount of protein was also obtained from plant-derived foods. Throughout the entire region, terrestrial animals provided bone for tools, teeth for decoration, and skins for clothing. Preferred consumption of marine foods appears to have been an adaptive strategy that arose as a natural consequence of prolonged residence on the seacoast for 10,000 years or more. Further, isotope studies of dogs from some archaeological sites show that they also appeared to have eaten mainly marine foods, indicating their close associations with humans.
