Abstract # 135:

Scheduled for Friday, June 22, 2007 05:00 PM-07:00 PM: Session 14 (South Main Hall) Poster Presentation

Seasonality in Long Calls by Titi Monkeys (Callicebus nigrifrons) in the Atlantic Forest of Southeast Brazil

C. B. Caselli and E. Z. Setz
State University of Campinas - UNICAMP, Ecology Program & Dept. Zoology , R. Bertrand Russel 1505, Campinas, São Paulo 13083-970, Brazil
     Many neotropical primates use long calls for within group (predator detection, group cohesion) and between group (food, space or mate defense or attraction) communication. C. nigrifrons live in family groups of 2 to 6 individuals, and males and females emit vocalizations in duets. Describing the variation in these calls may yield information as to their function. Vocalizations from several groups were registered from 5 am to 5 pm from April to December 2006 in a 30 ha area in Serra do Japi, São Paulo State. Titi monkeys often moved towards neighboring vocalizing groups (or playbacks), and counter called. Groups emitted long calls throughout the day (n=2281 in 646 field hours), with 86% between 6 and 12 pm, peaking between 8 and 10 am [6 calls/field hour; c2(11)=1038.2; p<0.001]. Vocalization amount was seasonal [low early in the dry season: Apr – June; high in the late dry season: July – Sept, peaking at 9.8 calls /hour; c2(7)=893.0; p<0.001]. Fleshy fruits diminish in the dry season, and increased vocalizations may be due to defense of scarce food. Alternately, long calls may relate to mate defense, but mating was observed only once in November. Infants were seen in July (dry season), November and December (early rainy season). These observations suggest that the long calls in C. nigrifrons may be used in territory defense. Supported by CAPES.