Skip Navigation
Johns Hopkins Bloomberg School of Public HealthCAAT

Animal Welfare Enhancement Awards - 2005 Recipients

Parsing the variables of illumination and cage height
Evan L. MacLean and Sheila J. Roberts
 Center for Cognitive Neuroscience, Levine Science Research Center, Duke University

Laboratory primates are frequently housed in double-tier arrangements in which there are considerable differences between the environments of the upper and lower-row cages. Although several studies have investigated whether the sum of these differences affects monkeys' behavior, no studies have addressed the two most notable differences of light and height individually to determine the relative importance of each. In 2 experiments we explore how monkeys respond to variation in illumination and height and test the effectiveness of a housing refinement aimed at equating illumination between upper and lower-row cages. In Experiment 1 we pit the variables of illumination and cage height against one another to determine if both or only one of these variables affects monkeys' location preference. In Experiment 2 we consider whether monkeys accustomed to the relatively darker environment of the lower-row prefer to spend more time in a well illuminated, 2-level activity module than monkeys accustomed to the relatively brighter environment of the upper-row. We then investigate whether an increase in illumination of the lower-row would positively impact monkeys' willingness to spend time in this area of the cage during periods of access to the activity module. The results of these experiments will enhance our understanding of the environmental factors that affect monkeys' psychological wellbeing and reveal the effectiveness of increasing illumination in lower-row cages to improve living conditions for monkeys housed at this level of the cage.