7 Changes In Cat Behavior to Look For

Be on the lookout for changes in these key areas of your cat's daily activities. A shift in behavior may indicate a potential health problem that warrants veterinary attention.


Most cat owners are extremely familiar with their cat’s normal day-to-day habits, yet witness the occasional moment of unpredictability and surprise.

However, when a cat’s normal behavioral patterns suddenly change and do not quickly return to normal, the change should never be ignored. Sudden alterations in your cat’s behavior can be indicative of serious medical or psychological issues requiring prompt veterinary attention.

As you may already know, cats are masters at hiding their pain and illness. Because they are both predators and prey, they adapted this as a crucial survival strategy. Cats may seem perfectly normal even when they are not feeling well, and can remain outwardly stoic until their suffering becomes intolerable. It is only then that they will start showing symptoms of distress.

Aging and Stress May Change Your Cat’s Behavior

When cats are sick or emotionally distraught, they can act depressed, become withdrawn, overly quiet, anxious or even extremely vocal. They may display unexpectedly aggressive behavior towards their owners and other animals in the household.

Sudden behavioral changes are usually triggered by the aging process or stress caused by any abrupt environmental change or variation in their schedules.

To learn more about these behavioral changes and some of the possible underlying conditions that may cause them, we reached out to Stephanie Borns-Weil, DVM, a specialist in animal behavior at the Cummings School of Veterinary Medicine at Tufts University.

Dr. Borns-Weil began our discussion with a short history about how these diminutive predators came to live with people thousands of years ago. “Because cats are skillful mousers, they controlled rodents and the other critters that were consuming the grain crops of farmers. In return for their hunting prowess, people fed them, and allowed them to come and go in their barns and homes, thus developing a symbiotic relationship,” explained Dr. Borns-Weil. “Even though cats were considered ‘friends,’ they were not yet invited to remain as indoor cats in households until the fancier cat breeds were developed. These cats were kept strictly indoors since the people who owned these purebreed cats were afraid that their valuable pets would be stolen.”

However, this indoor lifestyle has also required pet cats to adjust to our surroundings, a habitat that is by nature quite alien to them. As a result, they can develop a variety of physical and emotional problems.

1. Your Cat Stops Using the Litter Box

Dr. Borns-Weil explained that it is unnatural for cats to simply stop using the litter box. Although some people believe that this behavior is a sign of anger or spite, she reminds owners that cats are not vindictive. Cats that stop using the litter box are communicating to their owner that they are distressed in some manner.

She emphasizes that cats are fastidious about their “toilet habits,” so when a cat suddenly starts urinating or defecating outside box, this is a red flag that tells the owner that the cat needs veterinary attention. Certainly, it could be a matter of paying more attention to the cleanliness of the box itself, its location or the type of litter being used — but a medical workup is strongly advised first.

For example, Dr. Borns-Weil explained that cats who start urinating outside of the litter box may be doing so due to the pain of a urinary tract infection, kidney stones, feline interstitial cystitis or even a blockage. Some cats can start to associate the litter box with their pain, and therefore avoid using it. Stressed and insecure cats may start spraying urine on objects to mark their territories. If constipated, cats can also associate the litter box with pain and start defecating outside the box. Dr. Borns-Weil stressed that it is crucial that owners have their cat examined by a veterinarian to rule out any underlying medical problem before assuming this is simply a behavioral problem.

2. Changes in Your Cat’s Sleep Patterns

Adult cats generally spend 16 to 18 hours a day cat-napping and sleeping. Most cats will normally awaken when their owner enters the room, or when it is feeding time. Failing to react to these stimulations may indicate that something is wrong. Any significant illness may cause cats to sleep for longer or shorter periods of time.

Obese cats may sleep more due to pain or low energy levels. Changes in the areas where cats usually sleep can be indicative of pain from arthritis, or a fearful cat may suddenly choose to get away from another cat by sleeping in high places. To avoid contact with humans or other pets, cats who are in pain may start sleeping under the bed or in the closet, for example.

3. Your Cat Declines or Drastically Increases Grooming Habits

Cats are meticulous about their grooming habits and spend considerable time cleaning themselves. But dirty or greasy coats, hair loss, bald patches, not grooming at all or over-grooming can be signs of an underlying medical condition, or stress and anxiety. Excessive grooming can indicate a skin condition caused by allergies, fleas, dry skin and neurological conditions. Stressed cats may groom excessively because licking or grooming releases endorphins (the body’s own anti-anxiety hormone), causing the cat to feel soothed.

On the other hand, according to Dr. Borns-Weil, “An underlying health problem may cause a decrease in grooming. Overweight cats may have difficulty reaching some areas of their bodies, causing matting of the coat. These cats are also at risk of anal gland problems and urinary tract infections because it is hard for them to thoroughly clean themselves after eliminating. Older cats with dental or arthritic pain may also experience enough discomfort to cause them to stop grooming.”

4. Your Cat Increases Vocalization

Sudden increases in the frequency, volume or characteristics of the cat’s vocalization may be the symptom of an underlying illness such as asthma or an upper respiratory infection. Yowling may indicate a hearing loss, confusion or feeling lost. Persistent vocalization may be an expression of pain, discomfort or stress. Cats who are grieving may start howling and vocalize excessively as they search for a feline companion or family member.

According to Dr. Borns-Weil, “Although separation anxiety is not as common in cats as it is in dogs, cats can also experience separation anxiety. This may cause cats to vocalize excessively. Cats who are accustomed to having their owners at home most of the time may suffer separation anxiety when their owner gets a new job, for instance — suddenly leaving the cat alone most of the day.”

Since there are many reasons for sudden changes in a cat’s vocalizations, it is essential for the owner to seek prompt veterinary attention to ascertain whether excessive vocalizations are rooted in physical or behavioral concerns and to get the necessary treatment.

angry cat on a fence

© Annalisa Latella | Dreamstime.com

5. Changes in Your Cat’s Social Interactions

Most cats are delighted to interact with other family pets and their human guardians. However, cats who suddenly refuse social contacts, are uncharacteristically withdrawn or become aggressive are displaying major flags to which owners must pay attention. These sudden changes in a cat’s affable behavior can be caused by stress and anxiety caused by a new pet (or baby) being introduced into the household, changes in the household makeup, a death or divorce, seasonal changes, moving to a new home or pain and illness.

Dr. Borns-Weil points out that indoor cats often are more sensitive to changes in the household than indoor-outdoor cats. “The world is small for indoor cats, so change affects them more than indoor-outdoor cats. Outdoor cats can get away from things they don’t like. They can hunt, explore and mark their territory. Indoor only cats don’t have that luxury.”

Indoor-only cats living in a feline-enriched environment are much more able to tolerate changes. “Indoor-only cats need regular physical, emotional and intellectual stimulation to help keep them fit and in good spirits. Cat trees, shelves on the wall leading to places on which they can climb, cardboard boxes in which they can hide, window boxes placed in areas from which they can watch birds and scampering wildlife are all essential ingredients that make up an enriched environment,” explains Dr. Borns-Weil.

“Because cats are predatory animals, playing with them interactively with feather toys several times a day not only mimics natural hunting behavior, it facilitates the bonding process with the owner. It’s good exercise, too.”

Cat and dog eating food

© Monika Wisniewska | Dreamstime.com

6. Changes in Your Cat’s Appetite

Although the prevailing myth is that cats are “finicky eaters,” this is not actually the case. Healthy cats enjoy their meals and look forward to feeding times. Lack of appetite may be a sign of an upset stomach, stress, dental problems, intestinal parasites, a cardiac problem, ingestion of a toxic substance or an intestinal blockage. Separation anxiety and depression are among the leading causes of inappetence in cats.

On the other hand, an unexplained ravenous appetite can be caused by psychological problems or medical conditions such as diabetes, hyperthyroidism, or poor food absorption in the gastrointestinal system. Both of these changes in eating habits can be serious conditions that should be promptly evaluated and treated by a veterinarian.

7. Weight Changes in Your Cat

Sudden weight gain or loss is not normal for cats. Cats can be avid eaters, yet experience unexplained weight changes. Often owners don’t notice weight loss or gain, especially in longhaired cats with thick coats.

Some of the medical conditions that may cause unexplained weight loss are diabetes, inflammatory bowel disease, dental problems, upper respiratory infections, cancer, leukemia and feline immunodeficiency virus. Changes in diet, schedules or regular routine can also cause appetite loss.

While cats will put on weight from overeating and lack of exercise, unexplained weight gain also can be caused by fluid retention from heart disease, tumors or internal organ disease. Unexplained weight gain or loss should always be promptly evaluated by a veterinarian.


  1. Hi. Concerned about my 7.5 yo cat Evie who was a rescue that I adopted years ago through my vet in another state.
    When if he came to live with us she joined my pack of two poodles and another rescue kitty who was a neutered mail and in the beginning rejected her but very quickly the two became very very good friends. One by one my poodles and then my cat Grayson left the household through death and Grayson had to be rehomed because you refuse to stay inside and became ill outside and over and over and I couldn’t afford the medication. this left Evie and my one year old English Shepherd puppy. Recently the last member of my original pack died of cancer and evies behavior toward the English shepherd has become aggressive in a sporadic fashion. Never know when she’s going to go after the pup. What’s going on with Evie and what can I do to help her? Thank you.

    • Grief can also affect cats and other animals. You could try some pet rescue remedy. Also a feliway plug would help to keep your cat calm

  2. I have a 3 month old kitten that disappeared for one day she was back the next morning and now is withdrawn and will not hang out with the other cats and insist on coming in the house and it’s real mellow why is that when she has her brothers and sisters to play with but yet refuse to do anything with him now after that night she was gone

  3. Everyone loves to scream “Go to the Vet”, however vets cost money and some of us do not have the financial means to do so at the time. I only get paid once a month and it will be 3 more weeks before I can afford to take my cat to the vet.

    • If you can’t afford proper medical care for a pet, you can’t afford the pet. It’s not fair to the animal for you to keep it and not care for it. Priorities!

      • This response is heartless and unhelpful. I’ve spent so much money on vets over the years. Vets who don’t really seem to help the situation much unless it’s worms, or an ear infection, or something else relatively trivial. They often don’t really know what the problem is, even after a slew of tests for various things. It’s incredibly frustrating.

  4. Having issues with our cat. She’s 5 years old. Our 13 year old cat recently passed and they always got along so we were hoping to adopt another cat so that our 5 year old had company when i inevitable stop working from home. Fast forward, we ended up rescuing a mama cat (2 years old) and her two kittens (3 months old). It’s been two months, and out 5 year old is getting more and more aggressive towards the new cats and seems stressed out all of the time. I’m not sure what to do to help ease her stress. The new cats generally leave her alone and she has more than enough space to exist in rooms without them but she tends to skulk around the house all day growling and hissing (even when there are no cats in the room with her, or even at me) which is extremely unusual behavior for her. We brought her to the vet a month ago and he said she just needs time to adjust but I’m a little worried that the stress might be negatively impacting her.

      • Did anyone ever respond to this or did you find a solution? I’m in a very similar situation with our 3.5 year old cat. She also tries to play by swatting and chasing but it’s a little aggressive. I’m worried the streSs will change her form the sweet cat she’s always been.

      • My Rag Doll is exactly the same she growls and spits even when the new kitten isn’t in the room, it’s 8 weeks now and worse than ever. Tried plug ins. her fav food ect, she’s staying out longer and longer, I’m demented!!
        On top of it all we have lost our dog, she was old and ill. That has made Willow even worse if possible.
        Help anyone!

  5. My 12 year old cat has always done her toilet outside but has suddenly refused to go outside and is using her litter tray or even the floor. She was frightened by fireworks but that is a month ago. Do I need to take her to a vet.

  6. We have a 7 year old, formally feral, maincoon mix cat, Leo. Until recently he was the most affable cat we’ve ever had; however, about two months ago that started to change. We also have a formally feral two year old large black cat Draco, and we have two small dogs, one a Lhasa mix, Tiko, and the other a Chi-weeny, Lacey. The two small dogs like to chase our cats, but not harm them. For the past couple of months Leo will suddenly run up on Tiko, who is the beta, and he will attack him unprovoked. He will even jump him while he sleeps. He never bothers Lacey, the alpha, though. This is a sudden and major change in behavior. Also of note, he is completely cordial to everyone else, animals and humans. Any pointers?

  7. I have had my cat since she was born very loving. After I moved the only one she lets by her is me. I’ve lived in new place almost 2 yes she still hisses at trys to attack everyone. She even tries to attack my granddaughter kitten. Is there something physically wrong. She throws up at least once a week. Sometimes when I pick her up she’ll make sound like she’s in pain

  8. Recently, my cat has been shooting out her anus and rolling on the floor making some sounds and I don’t know what is wrong with her

    • Well sounds like something medically wrong. If you Suddenly shot out your anus, how would you handle it? ….. Hopefully by seeking medical attention.

  9. Hi there, so I have a 1 1/2 year old female cat, we have 2 other cats one of em is her mom. So both my girl cats are very very affectionate. Izzy (the baby) she would always be near me or sitting on my lap. We got another cat a male and they became best friends and her behavior was fhe same. Very loving and affectionate. We got her fixed (I was worried her personal would change) but still very loving afterwards. She got very very sick and almost died twice actually. They thought she had leukemia but thank God she did not. So she got better and was super lovey after that. All of a sudden we went to take a trip for a week and I had my friend check on em and had cameras placed around tje house to check on em ourselves. We’ll it was like as soon as we got back from our trip she changed. My other cat still affectionate (the mama) the boy cat we adopted he’s not very affectionate but is very playful. I’m wondering if I did something wrong. She used to sleep with me every night and follow me around everywhere and now the only time she wants any affection is when I’m in the bathroom( i know weird lol) but as soon as I’m in the bathroom she comes running. I know she had a rough first year. She was fhe runt and almost didn’t make it then she got sick. She also has gained a lot of weight in the gut area and I’m worried somethings wrong. She’s still pretty tiny for her age. Her brother is actually younger then her but he’s twice as big as her. But her belly is huge!! Any suggestions would be greatly appreciated. Thank you so mucj!!

  10. Our 2 year old female had a very small portion of catnip and became extremely aggressive towards her male sibling, to the extent of attacking him. We have to keep them separated in different rooms because as soon as she sees him she attacks. This has continued for three days now and she shows no sign of returning to the peaceful cohabitation that existed prior to her catnip experience. She shows no aggression towards my wife or me. She remains very affectionate towards us both. Aside from the aggression towards her sibling, she shows absolutely no other change in behavior or bodily functions. Is the catnip causing her change or can it be traced to some other problem?

    • I might be the fact that she’s coming into heat if she’s not fixed. But female cats tend to be more territorial and aggressive towards especially outside animals but even other pets in the household. Both female cats I had basically were in charge over their male counterparts.

  11. My 17-yr-old orange tabby neutered male cat has suddenly changed his behavior drastically…he was always very attached to his routine and mine… slurping water when I bathed, sleeping on the bed at my feet at night, always coming when I called him and knew when his “loving” times with me were. Now he sits almost on top of his food and water dishes, just across from his litter box. He let’s me pick him up, which he never did before and put him on my legs as I watch TV… he always used to lay beside me. He now stays in the living room/kitchen area and never goes into the other rooms in the house. He is very quiet and when he meows on rare occasions it is a low gutteral noise, not his usual perky sound. He is sleeping more and more, still using the litter box, sometimes has diarhea and seems to urinating less, tho’ he still drinks water. I tho’t he was dying, but he still can scurry quickly when he wants to (rare) and is grooming himself more and scratching a lot, also shedding. What is going on?

  12. My 2 year old cat is loving affectionate and literally loves to be held. She has a. Sister who was born at the same time. They are like two peas in a pod. I went to clean the litter box and she typically gets very excited about it but Out of no where she for the very first time started a fight with her sister and it was brutal and lasted several minutes. The fight became so bad that I tried to separate them. I had to go to the ER. FOR MY Iinjuries. That was two days ago and she has no signs of returning to her normal loving self. She has tried to attack her sister several times and she continues to be very aggressive and has attacked me she hisses constantly and shows signs of wanting to attack me again but she will come close to me one minute and the next she hissed and crouches down for attack please help me understand this behavior that happened for no reason

  13. Hi I have a 7moths male cat and was looking after a pregnant female cat and they both got along with each other and the female cat had the kittens and the male cat was alright but I see that the last 2days he kind off been a little different was just see they may be any a vices

  14. My cat is 5, perfectly healthy, but I put new flooring in my kitchen where his feeding bowl so are & he’s stopped eating as his usual routine, the flooring is highly patterned & he seems to be in a trance, is it possible this is putting him off his food or maybe the hot weather ?? He is a pure white cat ??


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