ASSESSMENT OF CAGE USE BY LABORATORY-BRED COMMON MARMOSETS (CALLITHRIX-JACCHUS)

The way in which breeding families of laboratory-born marmosets used t he space provided by their cages, and a small protruding 'veranda', wa s assessed in order to determine the popularity of the veranda as a fo rm of environmental enrichment, and the extent to which the marmosets confined themselves to only part of the cage. The veranda was found to be of enduring interest to the marmosets whose occupancy of this spac e was an order of magnitude greater than the rest of the cage. The upp er part of the cage was preferred to the bottom half. This preference was greater in larger cages and decreased when larger cages were tempo rarily reduced in size. It is unlikely, however, that the distribution of the occupancy of different parts of the cage resulted primarily fr om a fear of people in the holding room. The veranda, which was the mo st preferred place in the cage, was the nearest part of the cage to pe ople in the room. Occupancy of the lower part of the cage increased wh en human observers sat on the floor, suggesting that some of the marmo sets' behaviour comprised approaching, rather than avoiding, the obser vers, possibly for reasons of curiosity and social interaction.