The communicative function of some agonistic behaviour patterns in squirrel monkeys: The relevance of social context

Summary

The communicative functions of agonistic behaviour patterns of squirrel monkeys (Saimiri sciureus) are investigated in automated telestimulation experiments. The aim of this paper is to reveal how the context of a behavioural event-expressed in terms of the participating animals-has an influence on its communicative function. We included in our analysis animals involved in a behavioural event as sender and recipient of a certain signal, as well as the initiator-that is, the animal which caused the sequence in which the behavioural event in question occurs. Using this approach we found that

• 1. Animals in an experimental group form subgroups when taking part in the communication network, and the subgroups prove to be different, depending upon whether a male or a female initiates the communication process (Table 3).

• 2. The communicative meaning of the same behaviour pattern may vary, depending upon whether a higher or a lower-ranking animal performs or receives it.

• 3. Moreover, the same behaviour pattern exchanged between the same partners in the same direction may differ in its communicative meaning, depending upon whether a male or a female is the initiator. For example, the behaviour pattern “genital display” appears as a “weak dominance” gesture if it is directed from the dominant male towards a male initiator. However, it appears as a “triumph” gesture if directed from the dominant male towards a non-initiator animal regardless of its sex (see Fig. 9, and Tables 1 and 3).

The assignment of a functional label such as “triump” or “weak dominance” to a certain behaviour class in a certain context is thereby done in a purely operational manner (Table 7) on the basis of the outcome of several quantitative measures, each of which quantifies a relevant aspect of communication processes.