ABSTRACT
Primates can produce some surprising sounds, and when more than one of them get going they can make quite a racket. Even in the small Brazilian forest fragment in which I work, the marmosets whistle like birds, the muriquis neigh like horses, and the howler monkeys roar so loudly that they can be heard more than a kilometer away under the right ambient conditions. Describing the sounds primates make is a simple process compared to the challenge of deciphering what exactly it is they are saying to each other (Figure 10.1). Add to the difficulties of interpreting their complex vocal repertories a host of facial expressions, genital displays, and urine washing rituals, and you begin to get an idea of what constitutes primate communication.
