While playing together, marmosets may chase one another, pounce on one another or wrestle with one another. Sometimes they may even bite one another. The biting, however, is inhibited, non-wounding and nonaggressive. It is important to distinguish play behavior from actual aggression. Additionally, the biting and wrestling causes wounding.
Fighting often leads to serious injury to one or all contestants and is therefore very costly.
For this reason, primates are more likely to rely on threats and displays more often than actual physical combat. The common marmoset, like many other primate species, is not particularly aggressive and fighting is rare. When aggression does occur, it is usually associated with both aggressive and submissive behaviors and vocalizations. Social grooming is an important form of social contact. It helps to strengthen and form social bonds among group members and may even be used to ease tense interactions.