Cage Use and Feeding Height Preferences of Captive Common Marmosets (Callithrix j. jacchus) in Two-Tier Cages Hannah M. Buchanan-Smith and Carole Shand Department of Psychology University of Stirling Keith Morris Human Reproductive Science Unit Edinburgh, Scotland Determining appropriate feeding regimes has important welfare implications for cap- tive primates. This study examined the preference of food bowl heights in 6 pairs of common marmosets (Callithrix jacchus) housed in a 2-tier cage system. Given that marmosets are arboreal and spend most of their time in the upper half of their cages, we predicted that the marmosets would prefer a food bowl positioned at the top of the cage over one positioned at the bottom. We further predicted that this would be more apparent for the marmosets housed in lower tier than upper tier cages. Given a choice regarding where to feed, marmosets did prefer the top bowl to the bottom bowl; how- ever, when only 1 food bowl was presented, its position had no significant effect on the marmosets’ feeding behavior. In addition, contrary to the prediction, there were few differences in the marmosets’ feeding behavior in the upper and lower tier cages. Feeding the marmosets in a bowl at the bottom of their cage did not result in greater cage use. On the basis of this study, we recommend positioning captive marmosets’ food bowls high in the cage. JOURNAL OF APPLIED ANIMAL WELFARE SCIENCE, 5(2), 139–149 Copyright © 2002, Lawrence Erlbaum Associates, Inc. Requests for reprints should be sent to H. M. Buchanan-Smith, Scottish Primate Research Group, Department of Psychology, University of Stirling, Stirling, FK9 4LA, Scotland. E-mail: h.m.buchanan- smith@stir.ac.uk