A novel method for capturing and monitoring a small neotropical primate, the squirrel monkey (Saimiri collinsi)

Squirrel monkeys (genus Saimiri) are agile, arboreal primates that are seldom captured in the wild due to their small body size (<1 kg) and large, non-cohesive social groups (40-50 individuals). However, long-term studies on these primates often require captures and permanent identification of individuals, in order to monitor their behavior and health. Here we report on a novel trapping method successfully used to capture Saimiri collinsi, in Eastern Amazonia, Brazil. Our objective was to capture as many individuals as possible from one social group of approximately 50 individuals, ranging over 150 ha of terra firme forest. Captures occurred in November and December 2013. We habituated animals to feed on a large platform located in a 123.5 m(2) area enclosed by a green net (3 m high). Multiple individuals could freely enter and exit the area via four ropes affixed from surrounding trees to the platform. Once individuals were feeding inside the netted area on selected trapping days, the ropes were dropped remotely, eliminating their escape routes. We successfully trapped 21 different individuals of the social group (14 adults and 7 immatures) with this method. We conclude that this is a conceptually simple, effective method for trapping squirrel monkeys in most habitats, and possibly other small arboreal primates that live in large social groups. The present method was more effective than previous methods utilized to capture squirrel monkeys in the field, and has the advantages of: allowing for safe capture of several individuals simultaneously; enabling re-captures; releasing of animals as a group at the site of capture; use of soft netting which facilitates safe capture of the monkeys.