We studied the diet, activity budget, vertical ranging, and postural behaviour in relation to weather of the three-toed sloth (Bradypus variegatus flaccidus) in disturbed montane forest remnants (1150 m asl) in northern Venezuela. Sloths spent most (72.9%) of their time resting and had a nearly exclusive (99.4%) leaf diet. While resting they assumed a sitting -not hanging -posture mostly (90.2% of observations). Species of three families, Clethraceae, Cecropiaceae, and Clusiaceae accounted for 77% of feeding records. Young leaves (67.2%) accounted for most of the leaf diet. Activity and posture were dependent on weather conditions. Sloths fed more often during mid-day hours and tended to rest more at dawn and dusk. In northern Venezuela sloths tended to use more frequently the upper strata of the canopy, while in warmer lowland sites they use intermediate levels more often. They adopted postures that maximized exposure of ventral surfaces to incident solar radiation when sunny, but minimized their surface area by huddling when cloudy, foggy or rainy. We propose that sunning behaviour of sloths may speed up their fermentation rate, and ultimately, might have been an important selective factor in the evolution of derived upside-down posture of sloths.

Geophagy has been recorded in an increasing number of New World monkeys (Platyrrhini) over recent years, permitting a tentative analysis of ecological patterns. While geophagy has now been recorded in species representing all 4 platyrrhine families and a majority of genera, there is a marked tendency for it to occur in the larger-bodied Pitheciidae and Atelidae. Howlers (Alouatta) are responsible for almost a third of reports, which are concentrated in the more frugivorous species, Alouatta belzebul and Alouatta seniculus. Geophagy may also be relatively common in the spider monkeys (Ateles) and the pitheciids, which are specialised frugivores and seed predators, respectively. An overview of the available data points to a marked Amazonian bias, allowing for geographical differences in the number of species and field studies. This pattern is demonstrated most emphatically by Alouatta, for which there are almost as many reports as field studies in the Amazon basin, in stark contrast with Central American sites, which have a long tradition of fieldwork, but no published records of geophagy. There are also relatively few reports from the Brazilian Atlantic forest. Despite the growth in reports, and the patterns identified here, the functional aspects of geophagy in the platyrrhines still remain unclear.

No abstract

Moving back in time from the early colonial to the late pre-colonial period we evaluate the hypothesis asserting the migratory movement of Cariban-speaking groups from the Middle Orinoco River area towards north-central Venezuela. The explanation in vogue maintains that the migration followed fluvial routes and occurred between 1350 and 1150 BP (AD 600-800). We examine archaeological, linguistic, ethnohistorical, genetic, and ecological data seeking similarities between the Orinoco emigrants and their northcentral Venezuelan descendants. As a result, we propose an alternative terrestrial/fluvial route and suggest these events occurred between 1150 and 1050 BP (AD 800-900). The route first proceeded upstream along rivers of the central llanos and later followed a natural terrestrial geomorphological corridor into the Lake Valencia Basin. We argue that, while future interdisciplinary (especially archaeo-linguistic and bioarchaeological) research is needed to further assess the results of these analyses, the Orinocan descendants in northcentral Venezuela emerge as one of the most dynamic sociopolitical Cariban-speaking entities in all northeastern South America and the insular Caribbean on the eve of the European Conquest.

Since the fi rst long-term fi eld study of mantled howler monkeys carried out by Clarence R. Carpenter on Barro Colorado Island about 80 years ago, howler movement patterns and range use have been studied in several species and study sites throughout Mexico, Central, and South America. Howler monkeys often use small home ranges (<30 ha) and travel short distances each day (<1,000 m) compared with other atelines. Home range size, day range length, and patterns of use of space may vary both within-and between-species in response to differences in forest structure, patterns of resource distribution and phenology, the area of habitat available, group size, and population density. Within-species variability has been shown to increase with increasing sample size. In addition, howlers present a pattern of repetitive use of a limited number of routes to travel between feeding and V. B. Fortes