Calories delivered by nonhuman primate foraging enrichment: Data and methods to inform decisions concerning the dietary consequences of enrichment

Foraging opportunities are a key component of enrichment in captive nonhuman primates providing manipulative opportunities in which animals can engage in species-typical behaviors. Recent studies suggest captive NHP populations have increased body weight over time leading to negative health outcomes. Increasing food foraging opportunities provides added calories that can be estimated but often are not directly measured. We assessed 10 commonly used foraging puzzles for the amount of foraging material they held; evaluated the range of caloric content delivered; and determine the labor and usage cost of each. Five preparation areas were sampled. The amount of foraging material contained in each prepared puzzle was calculated by subtracting the average empty puzzle weight from the loaded puzzle weight. A detailed description of food content was used to illustrate caloric content. Larger prepared puzzles held more food (M=104.9 g) as compared to small volumes puzzles (M=59.8 g). Analysis of the weight of food applied and caloric content suggest larger puzzles do have the potential to provide increased caloric load; however, the added food from large foraging puzzles constitutes only 5%-10% of the daily k/cal dietary requirement. The study illustrates the importance of considering puzzle characteristics when selecting foraging toys and discusses the considerations of cost of puzzle deployment, maintenance and interactive benefit. The broad significance of our assessment suggests that calories from foraging opportunities are not excessive and can be managed by adopting standard serving sizes and scheduling intermitted presentation of non-nutritive enrichment options.