A threat is a challenge to another animal. Threats may be made by a dominant animal to reinforce it's position over a subordinate (particularly mounting); or by a territory holder to an encroaching individual (tail rattling is often seen in agonistic interactions between adjacent territory holders); or by a mouse trying to usurp territory or dominance from another animal.

 

The response of the recipient to the threat behavior divides agonistic interactions into two main classes:

1. Mediated aggression. In a stable hierarchy threat behavior will often lead to immediate fleeing or submitting by the recipent animal, which normally terminates the interaction. If the aggressor does not break off the interaction, the recipient may continue to attempt to submit or flee, and/or engage in defensive behavior such as crouching.
2. Escalated aggression. In forming, unstable, or shifting hierarchies, or when a mouse is intruding on territory, a threat behavior may lead to a retaliatory aggressive behaviors. The aggressor will normally respond with other aggressive behaviors, and the resulting interaction is clearly identifiable as fighting. This then either ends in death or fleeing andsubmission.