The effectiveness of auditory signals for long distance communication depends on environmental, biological and behavioral factors. Because the environment is not homogenous, it is expected that vocalizing animals would emit signals from locations (perches) that would facilitate call propagation and perception. Perching behavior has been widely documented in birds, but not in primates. The aim of this study was to ascertain whether golden lion tamarins - Leontopithecus rosalia (Linnaeus, 1766) - emit long calls from places (perch) within the forest strata that are higher above the ground with respect to places used for baseline behaviors. We compared the forest stratum (upper, middle and lower strata) and habitat type (hill, swamp and lowland forests) used for long calls with those used for other behaviors. The focal animal technique (n = 4) of 10 minutes with instantaneous sampling at two minutes were used if the subjects were not emitting long calls, and the all-occurrences technique if a focal individual emitted a two-phrase long call. Golden lion tamarins used all strata in all habitat types, including the ground, when they were not emitting long calls, but vocalized long calls most often from the upper strata, just underneath the canopy, in the three habitats studied. From a total of 29 bouts of long calls, 21 were initiated by individuals that were in the lower stratum; however, these individuals subsequently migrated to the upper stratum, while still vocalizing. Calling from the upper strata of the forest, just underneath canopy could improve sound transmission, perception, visual contact or a combination of these types of communication. Based on these considerations, we hypothetize that by placing themselves in the upper strata of the forest when emitting calls, golden lion tamarins enhance their likelhood to locate other callers, not only be improving sound reception, but also by increasing their chances to make visual contact with them.

A Mata Atlântica, apesar de ainda sofrer uma intensa devastação, abriga 261 espécies de mamíferos, sendo 73 endêmicos. Mamíferos de grande porte estão entre os mais vulneráveis à caça, perda de habitat e tráfico de animais. No Estado do Rio de Janeiro existem somente duas Reservas Biológicas de Mata Atlântica de baixada, a Reserva Biológica de Poço das Antas e a Reserva Biológica União. O presente estudo teve como objetivo avaliar a influência da prática da caça ilegal sobre a fauna de mamíferos nestas duas Unidades de Conservação. O levantamento populacional foi realizado utilizando o método de transecção linear e 375 quilômetros foram percorridos durante o período de dezembro de 2003 a janeiro de 2005. Os dados de estimativa de densidade populacional foram analisados no programa DISTANCE 5.0. Através de encontros visuais foram confirmadas 12 espécies durante o levantamento, sendo estas regularmente caçadas na região. As espécies que apresentaram maior densidade nas duas Unidades de Conservação foram o macaco-prego (Cebus nigritus Erxleben, 1777), o bugio (Alouatta guariba Lacépède, 1799), tatu-galinha (Dasypus novemcintus Linnaeus, 1758) e o tatu (Dasypus septemcinctus Linnaeus, 1758). As espécies mais raras ou ausentes foram a anta (Tapirus terrestris Brünnich, 1771), o veado (Mazama americana Rafinesque, 1817) e o queixada (Tayassu pecari Link, 1795). Evidências diretas e indiretas da ação da caça ilegal foram observadas nas duas áreas de estudo, indicando que a caça é uma prática comum nessas Reservas Biológicas. A sobrevivência a longo prazo dessas espécies é questionável, já que as populações remanescentes em fragmentos são pequenas e isoladas, o que as tornam muito susceptível à extinção mesmo sob uma baixa pressão de caça.

The Atlantic Rain Forest even though suffering intense devastation, shelters 261 species of mammals, 73 endemic. Large mammals were among the most vulnerable to hunting, loss of habitat, and wildlife trade. In the State of Rio de Janeiro there are only two Federal Biological Reserves of lowland Atlantic Rain Forest, the Poço das Antas Biological Reserve and the União Biological Reserve. The purpose of this study was to assess the presence and putative influence of illegal hunting on the mammals in these two Conservation Units. Surveys were conducted using a line-transect method; 375 kilometers were covered during the period between December 2003 and January 2005. The data for the population density estimate was analyzed using the program DISTANCE 5.0. Twelve species were confirmed through visual encounters during the surveys, whereas are regularly hunted in the region studied. The species that presented higher density were brown capuchin monkey (Cebus nigritus Erxleben, 1777), howler monkey (Alouatta guariba Lacépède, 1799), nine-banded long-nosed armadillo (Dasypus novemcintus Linnaeus, 1758), and the seven-banded long-nosed armadillo (Dasypus septemcinctus Linnaeus, 1758). The most rare or absent species were the brazilian tapir (Tapirus terrestris Brünnich, 1771), the red brocket deer (Mazama americana Rafinesque, 1817) and the white-lipped peccary (Tayassu pecari Link, 1795). In these two study areas both direct and indirect evidence of illegal hunting was observed, indicating that hunting is a common practice inside these Biological Reserves. The long-term survival of the hunted species is questionable, because the remaining populations living in fragments that are small and isolated, making them more susceptible to extinction even under low hunting pressure.