Why is my cat suddenly slinking, growling, and acting threatened?

It could be Jenna isn't feeling well, and that is making her grumpy. A sudden change in attitude including hiding and aggression can be a sign of a medical illness. I'd take her into the vet first thing in the morning to get checked out. Best of luck.

Poor Atta! Abnormal cat behavior can occur for many reasons, and often it is difficult to figure out. If her sister was out of the house she may have a weird smell to her, or if something startled Atta she may have projected that onto her sister. Whatever the reason, I would leave her alone for now. Put a litter box in the room where she is hiding along with food and water and just leave her be. If she is still acting off tomorrow, I would have her seen by her veterinarian as sometimes this can be caused by pain or a medical condition.

Thank you for submitting your question regarding Kitty Mucher. If she spends time outdoors, then I worry that she sustained an injury. Cat bite wounds are common and could explain her abrupt change in behavior. If she is not acting normal by the time you return home today, then she will need to see her veterinarian. If she does have a wound (and they can be hard to find), she will require treatment. I hope this information helps!

Thank you for submitting your question regarding Blue. She may have been stressed by your friend's visit. Even if she has met them before, visitors can be overwhelming to a cat. In this case, if she is eating and drinking normally, then give her some alone time to calm down. Let her seek you out for attention. Her behavior should return to normal in approximately 24 hours. If she is not eating and drinking, then I worry she is sick. This can create a behavioral change in a cat. In this case, I recommend that she sees a veterinarian today for a thorough physical examination. Based on these results, treatment can be started if necessary. I hope this information helps!

It sounds like something is making J-Cat nervous. I think I’m understanding that she has housemates but typically she gets along with them. It could be something outside that she heard or something she saw inside that is making her anxious. Even though she doesn’t seem obviously painful if this behavior continues I’d recommend seeing your veterinarian to rule out pain as a cause.

Cats may hide if scared or not feeling well. Try to determine is anything has changed around the house that may have spooked her. Any new people or pets, a move, or sudden change in schedule. If you can't think of anything then monitor health closely. Eating, drinking and litter box habits. Notice any vomiting or diarrhea. And if she is acting ill take her in for a vet visit.

The first thing I would do for now is put Attila in a room by herself with a litter box, food and water bowls, comfortable resting places, etc. and leave her alone for the next few days apart from coming in briefly to refill her food and water and change her litter. When cats become upset and aggressive like this, for whatever reason, it can take up to a week for them to fully calm down and return to normal - until then, it's best to leave her completely alone and give her plenty of space. Some cats can have serious aggression issues that are triggered by a strange or scary noise, an unusual smell, or anything else that startles them. It's possible that Attila may have had a scary dream that frightened her, or she could be painful due to a pinched nerve, arthritis, or some other issue that may have been aggravated by petting. If she calms down over the next few days and things return to normal with no further problems, you may not need to do anything else. If she is still acting aggressive a week from now, or if this becomes a recurring problem for her in the future, I would strongly recommend making an appointment with a veterinary behaviorist - he/she can evaluate Attila in person and help you determine what may be triggering these episodes, and will also give you some specific suggestions for managing her when this happens. Prescription medication is helpful for some cats with aggression issues, so this is something that could be discussed also. You can search for a board-certified veterinary behaviorist in your area here: www.dacvb.org