Bone’s Intrinsic Traits: Why Animals Eat Animals

Abstract

This chapter considers the nutritional needs that animal tissues meet for humans, beginning with a sketch of dietary shifts over the last several million years of hominin evolution, as given by stable isotope, parasitological, and fossil osteological evidence. Living animals store minerals in their bones and calorie reserves in the form of fat, and this chapter reviews the proteins and fats, fatty acids essential for neurological development, minerals, and vitamins offered by animal bodies to organisms that consume them. It argues that, because hominins’ large brains grow mostly during pregnancy and lactation, female reproductive fitness has probably been a major focus of selection. In the strongly seasonal environments that genus Homo colonized, animal foods provide nourishment when plant sources fail. However, a dominantly animal diet can incur physiological costs so serious as to require technological and social strategies to assure fat and carbohydrate intake when these are seasonally unavailable in the environment. Nutritional benefits of an animal body are not evenly distributed, and nonhuman and human consumers make strategic choices in response this variation. Chapter 5’s review of intrinsic qualities of animal bodies permits better understanding of how archaeofaunal assemblages reflect nutritionally driven choices, as will be covered in later chapters.