Pets in the Family: An Evolutionary Perspective

Abstract

Pets have become such a common component of modern family life that we tend to take them for granted. Nevertheless, from an evolutionary standpoint, pets present us with a paradox comparable to—though even more puzzling than—that posed by the phenomenon of adoption. In the latter case, one can at least argue that adoptive parents may derive deferred fitness benefits from the future contribution of adopted children to the family economy (Kramer, 2005). But in the case of adopted pets, such contributions appear to be minimal at best, whereas the level of investment in their care and sustenance is sometimes considerable. The paradox further intensifies when one considers that pet keeping is not confined to modern, affluent societies, but is widespread among subsistence hunters and horticulturalists whose opportunities to engage in nonfitness enhancing behavior would appear to be much more constrained. This chapter critically examines theories that purport to explain how pet keeping evolved and why it continues to persist and flourish in a wide range of cultures. Given the current state of knowledge, few firm conclusions can be drawn at this time regarding the possible adaptive consequences of pet keeping. However, it is possible to highlight future areas of research that may help to illuminate the functional significance (if any) of this intriguing behavior.