Visual cues are of primary importance in visual displays. Squirrel monkeys make these displays in an attempt to assert dominance or reduce tension between individuals.Visual cues involving facial expressions can be associated with fear or
aggression. A penile display, associated with spreading of the thighs, is considered to be a dominance gesture. Enclosures should provide a place for a submissive monkey to break the stare of a more aggressive monkey. Such places are
called “hide-boxes” and can be made from a piece of a large-diameter polyvinyl chloride (PVC) pipe or another impervious material.