Ethology is the study of “patterns of animal behavior in natural environments” (216), with a heavy focus on recognizing and tracking the development of particular traits through natural selection and adaptive evolution. It focuses on behavioral patterns in a particular species, and in contemporary models, largely focuses on the hormonal and neurological causes of these patterns.

Eugenics—a word that refers to “good genes”—is the practice of artificially selecting reproductive consequences geared toward a specific outcome. In the field of animal husbandry, this is not particularly controversial: Dogs are bred for particular traits designed to enhance their looks or affability, horses are bred for beauty and speed, and cows are bred for greater muscle density. In the arena of human eugenics, however, the practice has been largely condemned and outlawed, especially in light of the eugenic practices of the Nazi regime of the 1930s and 1940s.

A hypothesis is a well-founded explanation of a particular phenomenon that can be scientifically tested, resulting either in confirmation or disproof. Usually, “it is difficult if not impossible to prove a hypothesis with finality” (218), but the nature of a hypothesis is such that with enough evidence in its favor, it can be accepted as scientific fact unless proven false in the future.