Here are some possibilities:
Positive:
* Playmate: The older kitten may welcome a playmate, especially if they are an only cat.
* Learning opportunities: The older kitten could teach the younger one some cat etiquette and social skills.
* Mutual companionship: The kittens could form a close bond and provide each other with comfort and entertainment.
Negative:
* Jealousy: The older kitten may feel threatened by the new kitten and become possessive of their resources (food, attention, etc.).
* Aggression: In some cases, the older kitten may display aggression towards the younger kitten, especially if they are not properly introduced.
* Stress: The older kitten may feel stressed by the changes in the household and the presence of a new kitten.
Tips for a Smooth Introduction:
* Gradual introduction: Don't force the kittens to interact immediately. Let them smell each other under the door, then gradually increase their exposure.
* Separate spaces: Provide the kittens with separate litter boxes, food and water bowls, and safe spaces where they can retreat.
* Positive reinforcement: Reward good behavior and ignore any signs of aggression.
* Supervise interactions: Monitor the kittens closely during their first interactions and intervene if necessary.
It's important to be patient and understanding during the introduction process. It may take time for the kittens to adjust to each other. If you are concerned about the kittens' well-being, consult with a veterinarian or a certified cat behaviorist for guidance.