Contact calls: Information and social function

The focus of acoustic communication studies differs between birds and primates due to differences between the avian and primate social structures. Contact calls exist in almost all species independent of social structure, indicating their importance for animals. Contact calls contain various types of information about the sender. They function to keep groups cohesive or to help reunite visually separated individuals. In this review, we first describe the type of information contained in the acoustic structure of contact calls, and then we consider the function of contact calls in animals' social lives, particularly their function as identity advertisements.