Olfactory sensitivity for aliphatic esters in spider monkeys (Ateles geoffroyi)

Using a conditioning paradigm, the authors investigated the olfactory sensitivity of 3 spider monkeys (Ateles geoffroyi) for a homologous series of aliphatic esters (ethyl acetate to n-octyl acetate) and isomeric forms of some of these substances. With all odorants, the monkeys significantly discriminated concentrations below 1 ppm from the odorless solvent, and in several cases, individual monkeys even demonstrated thresholds below 1 ppb. The results showed spider monkeys to have a high olfactory sensitivity for aliphatic esters, which for the majority of substances matches or even is better than that of species such as the rat, the mouse, or the dog. These findings support the assumption that between-species comparisons of neuroanatomical features are poor predictors of olfactory performance.