Food-associated calls correlate with food preferences in cotton-top tamarins

Abstract

Food-associated calls in some birds and primates have been described as representational signals, with external reference to food objects. However, alternative interpretations suggest that these calls might also communicate an animal's preference for food or predict its subsequent behaviour. The vocal behaviour of cotton-top tamarins, Saguinus oedipus, was investigated in food and non-food related conditions. Recordings were made from nine adult cotton-top tamarins during presentation of a variety of foods. Two types of cells (C-chirps and D-chirps) occurred at a much higher rate than they did when no food was present or when animals were given non-food manipulable objects. Each of the two call types was associated with a different food-associated behavioural context. Great variation occurred within and between individuals in the number of calls elicited by different food types. Two-choice food-preference trials of six different foods presented individual tamarins with each combination of food pairs. All individuals had a transitive food preference hierarchy and each individual had a different preference hierarchy. Correlations between food preference rank and rate of calling were positive for eight of the nine animals, and the overall correlation of food preference with calling rate was significant suggesting that cotton-top tamarins use their calls to communicate honestly about their own food preferences.