The influence of behavioral enrichment on dry food consumption by the black tufted-ear marmoset, Callithrix penicillata (Mammalia: Callithricidae): a pilot study

Abstract

Stereotyped behaviors in captive primates are often caused by unsuitable conditions. Environmental enrichment has been used to reduce these behaviors, and also to increase the frequency of behaviors appropriate to the species. In this pilot study we evaluated whether behavioral enrichment influences food intake by the black tufted-ear marmoset, Callithrix penicillata (É. Geoffroy Saint-Hilaire, 1812), by calculating energy maintenance requirements. We evaluated 16 individually housed, healthy adult black tufted-ear marmosets, randomly divided into two treatment groups, one with behavioral enrichment and one without. The enrichment techniques included structural aspects, such as placing fixed and mobile objects in the cage and supplying dry foods in an enriched form, in order to stimulate cognition. Based on the metabolic weight of the animals, we calculated the energy requirements for their maintenance. The animals that received behavioral enrichment consumed more food than those that did not. We also observed that the animals that did not receive enrichment consumed 9.85% less food than had been calculated for energy maintenance requirements, while the animals that received enrichment consumed 24.97% more food than had been calculated. Results indicate that the use of behavioral enrichment items raised the energy requirements of the black tufted-ear marmoset and, therefore, the consumption of dry food, suggesting that environmental enrichment plays a role in stimulating food consumption. This conclusion should alert scientists, technicians and primatologists to the importance of controlling body weight of marmosets when introducing environmental enrichment to avoid overfeeding and obesity. To verify this conclusion, a study is needed with a longer time frame and more parameters, such as behavior observation and body weight.