Behavior, appetite, and urinary cortisol responses by adult female pigtailed macaques to cage size, cage level, room change, and ketamine sedation.

Pigtailed macaques (Macaca nemestrina) and longtailed macaques (M. fascicularis) show behavioral, ecological, and possible temperament differences, and their responses to the laboratory environment might therefore be quite different. We tested pigtailed macaques under the same conditions that were investigated in a previous study with longtailed macaques, using the same comprehensive set of physiological and behavioral measures of stress. First, eight adult females' adaptation to a new room in regulation-size cages was monitored, and in the third week their responses to ketamine sedation were measured. Then they spent two weeks singly housed in each of four cage sizes (USDA regulation size, one size larger, one size smaller, and a very small cage). Half of the subjects were in upper-level cages and the remainder in lower-level cages for the entire study. Cage size, ranging from 20% to 148% of USDA regulation floor area, was not significantly related to abnormal behavior, self-grooming, manipulating the environment, eating/drinking, activity cycle, cortisol excretion, or biscuit consumption. Locomotion and frequency of behavior change were significantly reduced in the smallest cage, but did not differ in cage sizes ranging from 77% to 148% of regulation size. The only manipulation to produce an unequivocal stress response, as measured by cortisol elevation and appetite suppression, was ketamine sedation. Room change and cage changes were associated with minimal cortisol elevation and appetite suppression. Wild-born females showed more appetite suppression after room change than captive-born females. No differences were related to cage level. Pigtailed macaques strongly resembled longtailed macaques except they showed weaker responses to the new room and cage change, probably because the pigtails had spent more time in captivity. These findings support the conclusion that increasing cage size to the next regulation size category would not have measurable positive effects on the psychological well-being of two species of laboratory macaques.