Sex differences in vocal structure in a callitrichid primate, Leontopithecus rosalia.

Four types of calls (long calls, chirps, chucks, and trills) from Golden Lion Tamarins (Leontopithecus rosalia) were analyzed for sex differences in structure. Six or more acoustic variables were analyzed for each call type. One or more variables from each call category differed significantly between the sexes. In addition, discriminant function analyses were conducted on male vs. female data for each call type. Long calls, chirps, and chucks from males and females were quite discriminable, but trills were not. That these differences exist is surprising given that callitrichid primates are otherwise quite monomorphic in structure and behavior. Possible functions served by sex differences in call structure include group censusing or assessing the sex of transient individuals.