Mixed-species exhibition of Neotropical primates: analysis of species combination success H. M. BUCHANAN-SMITH Psychology, School of Natural Sciences, University of Stirling, Stirling FK9 4LA, Scotland, United Kingdom E-mail: h.m.buchanan-smith@stir.ac.uk Many zoos worldwide exhibit New World monkeys in mixed-species exhibits, with monkeys, reptiles, birds or other mammals. Many of these exhibits are very success- ful, providing a more dynamic environment for the inhabitants and a more interesting and informative display for visitors. Analysis of previously published literature on the success and failure of species combina- tions reveals a higher success ratio for naturally associ- ating species, but that sympatry alone does not predict the likelihood of success. Nonetheless, careful consid- eration of choice of species and an enclosure purpose- designed or modified with features for the chosen species can increase success. Environmental enrichment can be designed to promote positive and natural interac- tions between naturally associating species. There are some precautions to be taken during the introduction of the species to increase the likelihood of compatibility, and continued monitoring of the exhibit with enclosure modification if necessary will increase the chances of longer-term stability. Key-words: enclosure design; environmental enrichment; mixed-species exhibit; New World monkey; polyspecific association. INTRODUCTION All zoo exhibits are of mixed species in one sense. Not only do other animals exist within the enclosures of the animals intentionally exhibited but also most enclosures have natural vegetation of different species! However, we generally refer to mixed-species exhibits as an intentional display of groups of two or more animal species that share at least a part of the enclosure simultaneously. Occa- sionally individuals of different species will be kept together for companionship or space reasons while waiting pairing with their own species. These, usually temporary, exhibits of individuals will not be discussed here. This paper summarizes the often anecdotal litera- ture on the benefits and potential risks of mixed-species exhibits in New World monkeys with other animals and describes how to minimize or avoid such risks, and promote positive interactions. CHOICE OF SPECIES FOR MIXED-SPECIES EXHIBITS, AND BENEFITS All wild Neotropical primates live in complex ecosystems, coexisting with numer- ous other species of animals. As such, any zoo that seeks to provide a naturalistic environment should consider mixed-species exhibits. However, animals in captivity are forced into much closer proximity than they would experience in the wild; they also have to spend less time foraging for food, and with no predation risk their behaviour can change, leaving more time for both intra- and inter- specific interactions. The relationship among coexisting animals in the wild varies, and this should be taken as a guide to compatibility. Some primates will simply coexist with the other animals, separated into ecological niches, for example by vertical separation or being active at different times, and without any direct interaction. These species are likely to make suitable enclosure cohabitants if the enclosure allows the natural separation to occur; for example, by providing adequate height, and appropriate and sufficient 150 NEWWORLD PRIMATES: BIOLOGY, BEHAVIOUR AND MAINTENANCE Int. Zoo Yb. (2012) 46: 150–163 DOI:10.1111/j.1748-1090.2011.00151.x Int. Zoo Yb. (2012) 46: 150–163 © 2011 The Authors. International Zoo Yearbook © 2011 The Zoological Society of London