Yes, rats do fight each other; conflict is a common and necessary part of their social existence. Rats, whether wild or domesticated, are highly social animals that form communities. This social structure requires mechanisms for establishing order, and fighting, particularly ritualized aggression, serves this function. While physical altercations can appear intense, they often occur within a predictable framework that prevents serious injury, maintaining a stable group dynamic.
The Role of Dominance and Social Structure
Much of the aggression observed in a rat colony is directly related to maintaining a social hierarchy. Rats establish a clear pecking order, often called a linear dominance hierarchy, which dictates access to resources and mating opportunities. Once this structure is established, aggression decreases because lower-ranking individuals consistently defer to the dominant ones.
This functional aggression is more common among male rats, who primarily establish the colony’s social order. The top-ranking individual, often called the alpha, maintains control through consistent dominance displays. Through these repeated, ritualized encounters, rats learn their place, and this acceptance of subordinate status helps the colony thrive by reducing constant conflict.
Primary Triggers for Aggressive Encounters
Aggression in rats is often triggered by specific stimuli that threaten the established social equilibrium or resource availability.
- Introduction of a new, unfamiliar rat into an existing colony, often called a “mischief.” Existing members may view the newcomer as a threat to resources or status, leading to confrontational behavior.
- Territorial defense, particularly among wild male rats defending their home range or nesting sites against intruders.
- The presence of sex hormones, especially in male rats nearing social maturity around six months of age. This hormonal surge can lead to increased aggression as they vie for dominance.
- Competition over limited resources, such as food, water, or prime nesting locations, can quickly escalate to fighting, particularly if the colony is experiencing scarcity or overcrowding.
- Stress from an unstable environment, such as a sudden disruption of the social order or illness, which can lower the threshold for aggression.
- Maternal aggression, displayed by female rats when defending their newborn pups from perceived threats.
Behavioral Signals and Physical Combat
Before a physical fight begins, rats employ non-physical signals to intimidate their opponent and attempt to resolve the dispute without injury. A rat preparing for conflict will exhibit piloerection, where the fur stands on end, making the animal appear larger. They may also engage in “sidling,” approaching the opponent sideways with lowered head, which is a precursor to a physical shove or kick.
If these warnings fail, the conflict escalates to physical engagement, often beginning with a “nose-off” standoff. This transitions into the characteristic “boxing” stance, where rats stand on their hind legs and use their forepaws to push or bat at each other. Fighting involves rapid grappling, often culminating in the dominant rat attempting to bite the subordinate’s flank or rump, which are less vulnerable areas.
The goal of most agonistic encounters is ritualized submission, not lethal injury. The subordinate rat signals defeat by fleeing, freezing, or rolling onto its back. This submissive posture usually ends the confrontation, allowing the dominant rat to reinforce its status through actions like chasing or dominance-related grooming. These brief interactions confirm the established hierarchy and maintain social stability.