Food quality, spatial deployment, and the intensity of feeding interference in yellow baboons (Papio cynocephalus)

Summary

Optimization models lead one to predict that the energy invested in competitive interference with feeding should increase as the quality of the contested food increases. This prediction was tested in a study of feeding interruptions involving juvenile yellow baboons (Papio cynocephalus) in Amboseli National Park, Kenya. For each of the 50 foods eaten by these young primates, 6 measures of food quality (energy content, protein content, yield, yield rate, processing value, and dispersion) and one measure of the spatial deployment of baboons (number of neighbors) were examined for correlations with 4 measures of the frequency and intensity of interruptions (interruption rate, probability of unsuccessful attempts, probability of appropriation, and probability of agonistic behavior). Disperson of food and the proximity of neighboring baboons had little or no effect on the frequency or intensity of interruptions. Food quality had negligible effects on the probabilities of appropriation and agonistic behavior. Yield characteristics were the best predictors of the success of attempted interruptions: attempts were least likely to be successful when processing the food was time-consuming. These results suggest that (1) the interrupter decides whether to interrupt on the basis of increasing its probability of winning the contest and decreasing its cost, and (2) the victim decides whether to resist on the basis of the time that has been and must be invested in harvesting the contested food item.