Data were collected at the Estação Biológica de Caratinga (see Strier 1999). The study group was composed of 8 adult and 2 subadult males, 12 adult and 5 subadult females, and 16 immature members. Spontaneous calls of adult individuals (n=322) were recorded from September to November of 1990, with a Marantz PMD430 cassette recorder and a Sennheiser ME-88 directional microphone. Acoustic analyses were conducted with RTS/Signal version 3.1 (Beeman 1989).
Calls within exchanges showed considerable acoustic variability and were formed by the combination of recurring elements (Mendes 1995, Mendes and Ades, in prep.). In this paper, analyses will focus on two distinctions (Fig. 1): a) short elements (less than 100 ms in duration) and long elements; b) staccatos (calls composed only of short elements; n=202), and neighs (at least one long element in their composition; n=120).
Data on the context of emission included: 1) the total number of calls in the exchange (an exchange was considered to be finished after a 10 second period of silence); 2) the maximum distance of other participants in relation to the recorded caller (0 to 20 m, 20 to 50 m, 50 to 100 m, more than 100 meters); 3) the presence of potential referents (large feeding tree, potential predators, members of other social groups, sexual receptivity of female callers).
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