Cognição espacial de Callithrix jacchus (Primates, Callitrichidae) em ambiente de Caatinga

Abstract

To increase efficiency in the search for resources, many animals rely on spatial abilities. When foraging, animals can explore resources both in small- (resources within the field of view) and large-scale space (resources outside the field of view). In addition to using spatial memory to recall the spatial location of resources in small-scale space, specifically in large-scale space, animals rely on mental representations created through the abstract representation of the space (coordinate- or route-based mental map) to navigate. Still, this navigation can be influenced by environmental factors. For animals, such as primates, who live in heterogeneous forests and consume resources with irregular distribution both in space and time, the ability to integrate spatial, ecological, and temporal information becomes crucial. Callithrix jacchus (common marmoset) appears here as part of a group (Callitrichids) especially interesting for studies on this topic. Besides having an omnivorous diet, with regular consumption of exudates, the same occurs in Caatinga, an environment with asynchronous phenological patterns and low availability of resources, such as fleshy fruits. In this context, we aimed to investigate, through two studies, the different spatial cognitive abilities both in small and large-scale space of this small neotropical primate. In the first study, we set up a field experiment, simulating a smallscale space foraging, in which we changed the spatial conformation of the available resource. We investigated whether common marmosets rely on short- and long-term spatial memory and one-trial learning. In the second study, we investigated the type of mental representation created by the species in large-scale space by recording each animal's behavior and spatial position throughout its activity period. We found that, in small-scale space, animals maintain spatial information on feeding locations both on a short- and long-term basis and can learn the spatial location of resources with just a single visit. When navigating in large-scale space, we found that animals use a route-based mental map, reusing route segments and turning points. The reuse of route segments and turning points was influenced both by distance to sites of interest (feeding, resting, and sleeping sites) and land cover. In general, the findings demonstrate that common marmosets rely on spatial abilities that help them remember and return to feeding places more efficiently both in small- and large-scale space. In small-scale space, these capacities seem to improve the search for dispersed resources in environments with fluctuations of food availability. In large-scale space, using a route-based mental map seems to benefit these animals due to the consumption of exudates that possess cluster distribution and are available all year round.