Jacobsen, K. R. 2010. The effect of environmental enrichment on the behavior of captive tufted capuchin monkeys (Cebus apella). Lab Animal 39(9), 269-277.

The authors provided different forms of environmental enrichment to six old laboratory male tufted capuchin monkeys (Cebus apella) and studied the behavior of the monkeys during a baseline period and during three enrichment periods. Each observation period lasted 5 d, with an interval of 6 d between periods. During the first enrichment period, the authors provided Buster cubes and wood cylinders with drilled holes filled with gum arabic. During the second enrichment period, monkeys were provided with a deep litter of bark shavings, and during the third enrichment period, they were given Buster cubes, wood cylinders and bark shavings. When provided with enrichment, the monkeys engaged in natural, species-specific activities and began to exhibit behavioral profiles that more closely resembled those of their natural counterparts. This suggests that their psychological well-being had improved and that group housing combined with environmental enrichment can improve the welfare of old laboratory tufted capuchin monkeys that were previously housed individually.