Vocal communication in New World monkeys

Abstract

Many features of the vocal communication systems of New World primates are similar to the most complex vocal systems known: human speech and bird song. This paper reviews the parallels between vocal communication in New World monkeys and phenomena of bird song and human speech. The long or loud calls of New World monkeys are functionally similar to bird song, being used for maintaining territories, for intragroup cohesion and for mate attraction. These long calls have features that allow for species, subspecies and individual recognition. While the long and loud calls of some New World primates fit the design features that maximize long distance transmission in tropical habitats, the long calls of most callitrichids are pitched too high for maximal distance of transmission. There are parallels in the ontogeny of bird song and the ontogeny of long calls. A highly variable set of calls is used by immature animals crystallizing into a stereotyped form with reproductive maturation. There is evidence of phonetic variation with categorical perception of different calls in pygmy marmosets. A rudimentary syntax and orderly turn taking behavior have been found in many New World primates. In squirrel monkeys there is evidence of a metacommunicative function of calls. The vocal communication systems of New World monkeys represent some of the most sophisticated vocal systems found in nonhuman primates.