Impact of a privacy panel on the behavior of caged female rhesus monkeys living in pairs

Thirty paired female rhesus monkeys were tested in a control situation when companions had no privacy, and in an experimental situation when they were offered the option to move behind a panel and be alone. Paired partners spent significantly more time in close proximity (same half of the cage) when the privacy panel was provided (means with panel = 76.0%/h vs. means no panel = 60.8%/h; p less than 0.005). At the same time, they were more engaged in affiliative interactions (means with panel = 37.4%/h vs. means no panel = 26.5%/h; p less than 0.025) while the incidence of agonistic interactions tended to decrease (means with panel = 0.3/h vs. means no panel = 2.2/h; p less than 0.1). It was concluded that rhesus monkeys have a need for companionship. They prefer to stay in close proximity with a compatible partner even though this may reduce their available cage space. It was further concluded that companions have no need for prolonged periods of visual seclusion, but occasional privacy is beneficial for their relationship.