On the Occurrence and Significance of Motivation-Structural Rules in Some Bird and Mammal Sounds

Abstract

The convergent use of harsh, low-frequency sounds by hostile animals and more pure tonelike, high frequency sounds by fearful or appeasing animals is discussed in an evolutionary context. It is proposed that many sounds in species' repertoires are evolved from motivation-structural rules derived from selection pressures favoring the use of communication instead of, or in conjunction with, fighting to attain resources. The use of this concept should further the appreciation of the relationship between sound structure and function.