Why is my kitten suddenly aggressive and hyper in its new home?

Sudden aggression and behavioral changes in cats can indicate pain or illness, so if you haven't already, a veterinary check up is best. If your cat checks out healthy, it may be there is a lot of stress causing your cat's behavioral issues. Making sure she has her own access to food, water, toys, treats, hiding spots etc from other pets or people is best. She is also still very young, and may just have a lot of energy/is still learning what appropriate behavior is. Ignoring bad behavior, increasing play and activity times, and rewarding calm, quiet behavior is best to teach her the right way to interact and to get out that excess energy. If the behavior continues even with this, speaking with a veterinary behaviorist is the best next step.

Poor girl! There could be something that has spooked her. Or she could be not feeling well. Or there could even be an internal conflict with another cat in the household. The first thing I would do is make sure she is healthy. I would see if your vet can look at her and make sure she isn’t painful, no infection, no fever, no urinary tract infection, etc. if she isn’t feeling well, this definitely can cause a change in behavior. If everything is normal then I would make sure she is getting along with everyone in the house. Make sure there are plenty of litter boxes as this is something they commonly will become territorial over. You can even put out some feliway diffusers which are pheromones they help calm down cats. Unfortunately these don’t work on everyone. You make also look into vetriscience composure treats as a natural calming supplement. I hope this helps!

Unfortunately, kittens that were bottle fed can be aggressive and not as friendly. You can try to put some feliway diffusers in the House and spray her sleeping areas. Feliway is a cat pheromone which can sometimes help to calm them. Also, give her more time. She has been moved from multiple house in her short life and now around new cats (they don’t usually remember family). This can be stressful and can take weeks for them to acclimate to. I hope this helps and she starts to get use to her new living conditions.

Sometimes when you bring a new animal into the house you have to be prepared for the fact that it may effect the personalities of other pets. Usually it is related to stress so you could try buying a pheromone diffuser to reduce this. Otherwise it could just be that she prefers the company of the kitten and this has changed her personality.

Moving into a new home can be very stressful for kittens - since she has only been with you for 4-5 days, it's likely that she's still adjusting and getting settled. It will take time for her to feel safe and comfortable in your home, so I would be patient for now and give her plenty of time to adjust. You can try using Feliway pheromone diffusers around the house to help make her feel more at-ease, as well as a natural calming supplement like Zylkene or Composure if she seems anxious.

Thank you for contacting Petco Pet Education Center, formerly Petcoach with your question about Brett. She is a beautiful girl! I'm wondering if the move has caused this change in behavior. Moving is very stressful for a cat, and that can lead to aggression. I'd try using Feliway diffusers around the home. These release calming pheromones that can help relax her. I'd pair that with a Sentry calming collar. This will release calming pheromones when in contact with her skin. If this doesn't help, then I'd have her seen by a vet for a health check. I hope this helps!

A sudden change in food can cause GI upset which may have led to pain or Pepper not feeling well. The stress of moving on top of that could certainly have caused the behavior you saw as well. Giving him some time to adjust to the new food (and switching it over gradually if you can) and new place may help him to relax, however if his symptoms continue or he shows signs of illness such as vomiting, diarrhea, lethargy, etc, then scheduling a vet visit is best.