Pines, M. K., Kaplan, G., Rogers, L. J. 2007. A note on indoor and outdoor housing preferences of common marmosets (Callithrix jacchus). Applied Animal Behaviour Science 108(3-4), 348-353.

This study examined the preferences of six pairs of common marmosets (Callithrix jacchus) from the colony at the University of New England, Australia, between their home cage and either a large, enriched, indoor room or a smaller outdoor cage. When given free access to move between their home cage and outdoors, the marmosets spent 70% of their day in the outdoor cage from the third day of testing until the end of the first 9 days of the first trial and also at 6 and 13 weeks later. Hence they showed a clear preference for the outdoor cage over the home cage. By contrast, when provided with a choice between the home cage and the indoor room, time spent in the indoor room decreased from 56% to 38% during the first 3 days of the trial and continued to decrease to less than 25% over the next week. The indoor room was visited more often than the outdoor cage (P = 0.001), but the visits were of shorter duration (P = 0.005), and were more often made by just one of the pair (P = 0.001). The results demonstrate that the marmosets had a strong preference to go outdoors during the day and did so without habituation, whereas a larger enriched indoor room apparently decreased in attractiveness to them.