Evidence for a spatial memory of fruiting states of rainforest trees in wild mangabeys

Abstract

We investigated the ranging behaviour of two groups of wild mangabey monkeys (sooty mangabeys, Cercocebus torquatus atys, and grey-cheeked mangabeys, Lophocebus albigena johnstoni) relative to a number of preselected target trees within their home range. We observed the groups' visiting patterns and speed when they approached within a critical distance of a target tree as a function of the tree's fruiting state. For both groups, the likelihood of coming into sight or actually entering these trees was significantly higher if fruit was available. Target trees with fruit were also approached significantly faster than were trees without fruits. These behavioural differences were unlikely to be the result of auditory, visual or olfactory cues available over long distances, suggesting that monkeys relied on spatial memory to (1) relocate fruit trees and (2) distinguish between trees that had and had not carried fruit in the immediate past. Results further indicated that the monkeys clearly distinguished between different types of fruit-bearing target trees. We suggest that the monkeys used memory of previous feeding experience to assess each tree's differences and were able to anticipate changes in fruit quality. We found no evidence that individuals belonging to a particular age or sex class led the group towards trees with fruit more often than did others.

Foraging Cognition in Nonhuman Primates

“…Unripe figs are attractive to these monkeys because some of them contain weevil larvae or edible seeds. Monkeys have to inspect each fig individually, an interesting fact for the purpose of cognitive studies, because it effectively rules out the possibility that the monkeys responded to long-distance visual or olfactory cues (Janmaat et al, 2006a). In addition, the authors also found that the average speed with which the group approached such trees was significantly correlated with their average prior feeding experience in that tree (Fig.…”

“…Similar suggestions for a rudimentary ability to anticipate future events have also been made for wild primates, but only a few good empirical studies are available (Janmaat et al, 2006a;Janson, 2007;Noser & Byrne, 2007b;Sigg & Stolba, 1981;Wrangham, 1977). Temperature and solar radiation influence ripening rates of fruits as well as the maturation of insect larvae inside them (e.g., Adams et al, 2001;Diaz-Pérez et al, 2002;Houle, 2004;Mazzei et al, 1999;Morrison & Noble, 1990), making the emergence of edible fruits somewhat predictable.…”

“…Because the fig trees were approximately 700 m from the sleeping site, visible to human observers only from short distances, it was unlikely that the monkeys were guided by any secondary cues (Noser & Byrne, 2007b). In another study, the ranging behavior of sooty mangabeys was studied in relation to Anthonota trees with empty crowns (Janmaat et al, 2006a;Fig. 4.5).…”

“…Most primates, including typical leaf-eaters, consume considerable amounts of fruits as part of their daily diets (e.g., Korstjens, 2001). Fleshy fruits and the arthropods that associate with them are highly nutritious, which provide arboreal animals, such as primates, birds, and bats, with a stationary and relatively reliable source of energy (Janmaat et al, 2006a). Primates and fruiting trees have shared a long evolutionary history, and the arrival of angiosperm fruits and flowers may have been of particular importance in primate evolution (Soligo & Martin, 2006;Sussman, 1991Sussman, , 2004.…”

Les mones de Lowe (<i>Cercopithecus campbelli lowei</i>) utilisent une stratégie de fourragement optimale dans la forêt Réserve de l’Université d’Abobo-Adjamé, Côte d’Ivoire

“…Cela paraît peu probable que les odeurs soient perceptibles à une distance relativement longue et que la visibilité soit suffisante pour une estimation correcte de la qualité des milieux. Janmaat et al (2006a) ont estimé la distance maximale de détection des odeurs des fruits par les mangabeys à moins de 20 mètres. Lorsque les contraintes du milieu sont importantes à l'instar de la faible visibilité dans les forêts tropicales, de nombreux primates développent des capacités cognitives appropriées.…”