Social Behaviors

Overview and Meaning

When observing social behaviors, it is important to:

  1. Define social interactions and functional groups.
  2. Identify the fundamental differences between interactions.
  3. Explain why interactions vary between groups and list the possible group combinations.
  4. Outline the organization of the interactions section.
Mice are social creatures by nature. When they are group housed, mice perform an array of behaviors that do not occur in singly housed situations. These additional behaviors are termed social interactions, and each interaction is a functional group. Each social interaction (or functional group) consists of the individual behaviors between two or more mice, known as the actor(s) and the recipient(s) inside a home-cage.

Unlike the functional groups of the individual behaviors section, social interactions cannot be divided down or isolated to one individual's behavior. The reason being is that an social interaction is a combination of acts and postures that influence each group member's behavioral sequence. (This would be analogous to describing a sporting event but only from the perspective of one player from one team). In a group interaction, the same individual acts and postures can occur in different situations. However, it is the combination of these acts and postures that form a unique social interaction. For example, a recipient can crouch in either an aggressive or allo-grooming situation. This means that it is the actor's behavior and posture that determines whether it is an aggressive or allo-grooming interaction. In scenario 1: If the actor is attacking the crouching recipient, then it is classified as an aggressive interaction. Compared to scenario 2: If the actor is licking the recipient's fur, then the crouching mouse is being groomed.


Social interactions vary depending on the conformation of the mouse group, and in laboratories, there are only a few group housing combinations. Within a group housing situation, the type of cage occupants are the factors that determine the combination of acts and postures. These factors include the quantity of occupants, the dominance hierarchy, age (weanlings or adults), and sex ratio (same sex siblings, breeding pair, or harem). Depending on these factors, some interactions are not possible or will vary compared to another group. Here are some examples: maternal interactions are not possible if the cage occupants consist of only weanlings, or the aggressive interactions will differ between a breeding pair cage versus a same sex sibling group.