The central question posed by this chapter is whether some physical properties of sound have consistent, species-independent effects on the response of an animal receiver. Research on professional animal trainers showed that trainers, of many linguistic and geographic backgrounds, used short, rapidly repeated broadband notes to stimulate motor activity and longer, continuous narrow-band notes to inhibit activity. Controlled tests on laboratory-raised domestic pups supported the hypothesis that short, rapidly repeated notes stimulate motor activity in domestic dogs (Canis familiaris). These studies are discussed in relation to the use of the same acoustic structures by nonhuman animals, and the hypothesis that some sounds are particularly effective in influencing the internal state and subsequent behavior of the mammals and birds who hear them