Interspecific interactions and welfare implications in mixed species communities of capuchin (sapajus apella) and squirrel monkeys (saimiri sciureus) over 3 years

Abstract

Species have complex relationships with others in the wild, and some such as capuchin (Sapajus apella) and squirrel monkeys (Saimiri sciureus) naturally choose to associate with each other. There are a number of benefits of exhibiting such species in correspondingly mixed communities in captivity to enhance welfare through increased social complexity, which is potentially environmentally enriching in restricted captive enclosures. Monitoring the interactions between species is critical, however, particularly when members of one species are considerably larger and potentially more aggressive than the other. We report on the frequency and nature of interspecific interactions between S. apella and S. sciureus during four time periods over 3 years (2008-2010) following the formation of two mixed species groups at the ‘Living Links to Human Evolution' Research Centre in Edinburgh Zoo, Scotland. Both the rate and the distribution of interspecific interactions among aggressive, affiliative and neutral categories of behaviour varied over time (P < 0.05). We predicted that S. apella would engage in more interspecific, particularly aggressive, interactions than S. sciureus than vice versa, as they are the larger, more social species and have a more pugnacious temperament. This was the case overall (P < 0.05), and particularly in 2009 and 2010. We predicted that affiliative interactions would increase over time as the number of youngsters increased and as the youngsters grew up together, establishing equable relationships and "territorial" boundaries. The data did not support this prediction. Both the most affiliative and least aggressive interspecific interactions were observed following internal enclosure refurbishment in 2008 and hence we argue that good enclosure design and husbandry is the most important factor in promoting positive interactions between individuals in mixed species groups. We conclude that long-term monitoring is important, and when combined with appropriate husbandry and enclosure upkeep, the welfare of individuals is enhanced in mixed species groups by the presence of other species.