Capuchin and Marmoset Monkeys are a small, but highly intelligent species of monkey that are kept as exotic pets and often for medical research. They are complex creatures that have a lot of specific requirements that make it nearly impossible to replicate their natural habitat and stimuli. They are well known for their distinct musky odor they use to differentiate one another and their foul smelling urine they use to mark their territories, a trait that can be tamed with diligent training. Keeping a Marmoset is like having a child. They live to be up to 18 years of age in captivity and require constant attention in the form of exercise, activities, and training.