Successful acquisition of an olfactory discrimination paradigm by spider monkeys, Ateles geoffroyi.

The present study demonstrates that an operant conditioning paradigm-originally designed for assessing olfactory performance in an Old World primate, the pigtail macaque-can successfully be adapted for use with a New World primate, the spider monkey. Using a task based on a food-rewarded, two-choice discrimination of simultaneously presented odor stimuli, Ateles geoffroyi is capable of learning to discriminate between objects on the basis of odor cues. Moreover, animals could readily transfer to new S+ and S- stimuli, and could remember the significance of previously learned odor stimuli even after a 4-week break. We could also show that this method is suitable for obtaining reliable measures of olfactory sensitivity. Our results indicate that A. geoffroyi clearly outperforms Macaca nemestrina with regard to the speed of initial task acquisition and the ability to master transfer tasks, and shows a sensitivity to a food-related odorant which matches that of other primate species.