Marmosets are a member of the primate family and are one of the smallest monkeys. These monkeys are semi messy animals and can be somewhat trained to defecate in a given area. Their urine has a strong odor, and some people will use special monkey diapers. They scent their areas by rubbing their perineums over everything: toys, food dishes, bedding, stuffed animals, furniture, rugs and caging.
They are intelligent and need stimulation. Interaction can be supplemented with toys, but if a marmoset is kept as a pet by themselves, it will rely on the human family to become its family group.