Influence of tannic acid concentration on the physicochemical characteristics of saliva of spider monkeys ().

Tannins are a chemical defense mechanism of plants consumed by herbivores. Variations in salivary physicochemical characteristics such as pH, total protein concentration (TP), and presence of proline-rich proteins (PRPs) in animals have been reported as a mechanism to protect the oral cavity when consuming food with variations in pH and tannins. Variations in salivary physiochemistry as adaptations for consuming tannin-rich foods have been found in omnivorous and folivorous primates, but have not yet been reported in frugivorous species such as spider monkeys.

Forgetting curve in spider monkeys (Ateles geoffroyi): Effects of delay but not the amount of information.

The forgetting curve is a phenomenon in which animals fail to retrieve information about an event as time passes. We tested this effect in spider monkeys () in a task where they had to retrieve a reward hidden in a container after a delay. We combined different delays (0, 5, 10, 20, and 30 s) and different numbers of containers in which the reward could be hidden (2-6) and tested their effects on the accuracy in retrieving the reward.

Female reproductive energetics in mantled howler monkeys (Alouatta palliata): A follow-up study.

Objective: Reproduction entails several challenges to primate females, among which energetic costs are remarkable at certain stages of the reproductive cycle. Still, females may use behavioral and physiological strategies to cope with those challenges. We had previously reported covariation between female energetic condition through the reproductive cycle and time-budget adjustments in mantled howler monkeys (Alouatta palliata).