Possible Reasons for Aggression:
* Territoriality: Mice are naturally territorial, especially females. Even if they were initially friendly, as they mature or establish dominance, they might become more aggressive to protect their space and resources.
* Hierarchy: In a multi-mouse group, there's often a clear hierarchy. The dominant female might be aggressive towards the others to maintain her position.
* Stress: Stress can trigger aggression. Factors like overcrowding, lack of hiding places, insufficient enrichment, or changes in routine can lead to tense behavior.
* Health Issues: Pain or illness can make mice more irritable and aggressive.
* Individual Personality: Some mice are just naturally more assertive than others.
Steps to Address the Aggression:
1. Observation: Carefully observe your mice. Note the triggers of the aggression, who is involved, and the severity of the aggression. This will help you identify potential causes.
2. Spacious Environment: Ensure your cage is large enough for all three mice to have their own space. Add multiple levels, hiding places, and nesting materials.
3. Enrichment: Provide plenty of enrichment items such as chew toys, tunnels, running wheels, and foraging opportunities to keep your mice mentally stimulated and reduce stress.
4. Feeding: Feed your mice in separate locations or provide enough food that everyone can eat at the same time to reduce competition.
5. Socialization: Continue to work on socializing your mice, but do so gradually and under your supervision. You can use a neutral space like a carrier or a playpen for short periods.
6. Monitor Health: Watch for signs of illness or pain in your mice, which could contribute to aggression.
7. Separate If Necessary: If the aggression is severe and you can't manage it, you might need to separate the aggressive mouse for a period of time.
8. Professional Help: If you're struggling to address the aggression, consult a veterinarian or an experienced rodent behaviorist.
Important Notes:
* Hand Washing: While washing your hands before handling your mice is a good habit, it's not the primary factor in aggression.
* Time and Patience: It takes time to socialize mice. Be patient and consistent with your efforts.
* Safety First: Always prioritize the safety of your mice. If there's a risk of severe injury, you may need to separate them.
Remember, observing your mice carefully and understanding their behavior can help you address aggression effectively. If you're unsure about any aspect of your mice's behavior, it's always best to consult a veterinarian or a rodent expert.