...are traditionally viewed as mainly visual animals with a poorly developed sense of smell. This view is especially based on an interpretation of neuroanatomical features, such as the relative size of olfactory brain structures, or on genetic features, such as the number of functional olfactory receptor genes. However, a positive correlation between measures of neuroanatomical or genetic features and olfactory performance has not yet been found. In recent years an increasing number of studies question the widely held view that olfaction plays only a small role in the daily life of non-human primates. More and more evidence from non-human primate species indicates that the sense of smell is involved in food identification and selection and in several social interactions.

Several studies demonstrated that spider monkeys (Ateles geoffroyi) possess a well-developed olfactory sensitivity for monomolecular solutions such as aliphatic esters, alcohols and aldehydes, carboxylic acids, ketones, monoterpenes, steroids, thiols and indols, as well as alkylpyrazines, “green” odors, and amino acids. Further, these studies showed that spider monkeys have an excellent long-term memory for odors, is capable of rapid odor learning, and has an outstanding ability to distinguish between different degrees of ripeness in fruits based on their odors.

...include several volatile metabolites produced by numerous strains of fungi species. Substances like 3-methyl-1-butanol, 1-octen-3-one, 3-octanone, 1-octen-3-ol and trans-2-octen-1-ol are quantitatively prominent volatiles produced by fungi belonging to Aspergillium, Penicillium and Deuteromycota taxa. However, other chemical compounds are also secreted by fungal species when exploiting a food item. Mycotoxins are secondary metabolites produced by fungi and are known to pose health hazards to the organisms that ingest them. Such compounds are reported to be a defense mechanism of fungi against other organisms, as well as a protection mechanism to secure the food resource. Besides, fungal species are also known to decrease nutritional content of the food material they develop in.

Thus, considering the potential dangers of spoiled food, frugivorous animals need to detect and avoid ingestion of spoiled food items. It is well-established that spider monkeys, a frugivorous New World primate, rely on their sense of smell in the context of food selection. Further, spider monkeys have a higher sensitivity to putrefaction-associated odorants than to other studied odorants, indicating an adaptation to the detection of degraded food material. Therefore, spider monkeys may have also adapted a high sensitivity to detect the odorous volatiles produced by fungal growths in food.

(1) to determine olfactory detection thresholds in spider monkeys for mold-associated odorants,

(2) to assess the impact of molecular structural features on detectability of the tested odorants,

(3) to compare the threshold data obtained here to those of other species tested previously on the same set of odorants and to evaluate the impact of the number of functional olfactory receptor genes on olfactory sensitivity.