My unneutered cat lost weight & stopped eating. What's wrong?

While loss/grief can certainly cause behavioral changes in cats, losing weight, not eating and urinating everywhere make me worry there is an underlying health condition such as a urinary infection that is causing him distress. Not being neutered can also lead to marking behavior/stress if there is a female in heat nearby. It is a good idea to have a thorough exam done along with bloodwork, X-rays and urine tests potentially to determine if there is any health issue. If he checks out healthy, spending more time together may help him to relax some, as well as using a pheromone diffuser such as Feliway to help with the marking behavior/stress. If you think he'd benefit from a friend, gradually introducing a new cat may help as well, but can also be stressful.

Your cat might have something going on with his mouth or teeth, or may have a urinary tract disease or some other metabolic issue. If he is losing weight, you should have blood work and a urine test done to make sure he doesn't have an infection or other issue causing him to stop eating as well as he was. Otherwise, the increase in wanting attention is not necessarily a bad thing or a sign of illness.

If he is not neutered then I would be suspicious that there is an in heat female somewhere that he is spending time and energy trying to get to. However, there are certainly other possibilities. I would encourage you to have him evaluated by your veterinarian to make sure there isn’t something medically concerning going on, and then potentially consider having him neutered. Best of luck and thank you for using Pet Coach.

I'm not sure how old Carolus is, but unfortunately it's very common to see this kind of behavior change in unneutered males once they reach social maturity - he is probably out looking for females to mate with, or fighting with other male cats, as both of these are more important to him right now than anything else. I would strongly recommend having him neutered when you are able to - this should curb his tendency to roam and not come home, and will make him a much better pet overall :)

Petey is a very handsome boy! Kittens do start weaning off their mother's milk around five weeks of age, so that is normal and wouldn't likely be a cause of him being skinny. He could be yowling at night because he's intact and sexually mature. He's letting you know he wants to go outside to prowl for females. To stop that behavior, I would have him neutered. Keep in mind as well that intact cats mark their territory with urine, and he could start spraying around the house. That's a very hard smell to get out, and neutering him will stop that. As for being skinny, he may naturally be a thinner cat or he could have intestinal worms. Those would cause him to have trouble gaining weight. I would give him a deworming treatment if he isn't up to date on them, and you can get one from your vet's clinic. I'd also recommend a health check with the vet just to make sure everything is ok with him health wise. I hope this helps :-)

Yes, indeed a cat that is not spayed and has to spend a lot of energy by going through heat will lose weight. If you do not intend to breed her, you should have her spayed, especially since cats will stay in heat until they get bred. She will be happier when she does not have to go through constant heat.

Hi there and thank you for using Petco Pet Education Center, formerly Petcoach to address your concern. It is possible that someone else is providing him with food as well and that is the reason he is not returning for all of his meals with you. He also may be sick, dealing with an infection or systemic disease. If you can catch him and bring him to the veterinarian, that would be ideal so that the most appropriate diagnostic and treatment recommendations can be made. I hope this helps guide you in the right direction. Please let me know if you have any other questions or concerns and I would be more than happy to help you further.