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. fascicul aris) show behavioral, ecological, and possible temperament differences, an d their responses to the laboratory environment might therefore be quite di fferent. We tested pigtailed macaques under the same conditions that were i nvestigated in a previous study with longtailed macaques, using the same co mprehensive set of physiological and behavioral measures of stress. First, eight adult females' adaptation to a new roam 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 size s (USDA regulation size, one size larger, one size smaller, and a very smal l cage). Half of the subjects were in upper-level cages and the remainder i n lower-level cages for the entire study. Cage size, ranging from 20% to 14 8% of USDA regulation floor area, was not significantly related to abnormal behavior, self-grooming, manipulating the environment, eating/drinking, ac tivity cycle, cortisol excretion, or biscuit consumption. Locomotion and fr equency of behavior change were significantly reduced in the smallest cage, but did not differ in cage sizes ranging from 77% to 148% of regulation si ze. The only manipulation to produce an unequivocal stress response, as mea sured by cortisol elevation and appetite suppression, was ketamine sedation . Room change and cage changes were associated with minimal cortisol elevat ion and appetite suppression. Wild-born females showed more appetite suppre ssion after room change than captive-born females. No differences were rela ted to cage level. Pigtailed macaques strongly resembled longtailed macaque s except they showed weaker responses to the new room and cage change, prob ably because the pigtails had spent more time in captivity. These findings support the conclusion that increasing cage size to the next regulation siz e category would not have measurable positive effects on the psychological well-being of two species of laboratory macaques. Am. J. Primatol. 52:63-80 , 2000. (C) 2000 Wiley-Liss, Inc.