Welcome to our weekly 'Ask a Vet from the SF SPCA' feature on 7x7.com. Dr.Jeannine Berger, DVM, DACVB is a board certified veterinary behaviorist who counsels guardians whose pets’ issues are beyond the scope of training. Think of her as a pet shrink…at your service. Ask your own questions in the comments!

Q: I have noticed that my young male cat's tail has become fluffy more recently. My understanding is that the fluffy tail is body language. What’s it saying? We have another cat, and I have noticed that they are roughhousing a bit more recently. How do I know if they're playing or fighting?

A: First of all I would recommend that you take your cat to the vet to have him checked out, the fluffy tail can certainly be a behavioral sign, but also it could mean that your cat is not feeling well for any number of reasons. If you can determine any behavioral triggers coinciding with the fluffed tail, such as the sight or smell of an unfamiliar outdoor cat, then you should take measures to avoid letting your cat have contact with that outdoor cat. You might have to block his view of the outside or keep the outdoor cats away with deterrents. Sometimes the tail can stay fluffed up for a while after an arousal situation.  If an outdoor cat is indeed causing your male to be more anxious or feeling territorial or aggressive, he might redirect towards your other cat.

To determine whether they play or fight, watch their body language closely. As long as both cats seem comfortable with their interactions, they are most likely doing okay. But if you start noticing that they don't want to be next to each other for sleeping or resting, or if they don't groom each other, or worse if one cat starts hiding from the other, do something. If you start to see defensive and fearful body language, you need to find out why their interactions have changed. If one cat is very playful and the other cat is less playful, you might want to be your cat's playmate and give him or her some scheduled, interactive playtime. If cats are spending time next to each other, resting, sleeping and grooming, that is a good sign.