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Home > Cats > Why Does My Cat Hiss & Growl at Strangers? 7 Potential Vet-Reviewed Reasons & Solutions

Why Does My Cat Hiss & Growl at Strangers? 7 Potential Vet-Reviewed Reasons & Solutions

Abyssinian cat hisses

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Dr. Maja Platisa

Veterinarian, DVM MRCVS

The information is current and up-to-date in accordance with the latest veterinarian research.

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Feline emotions are mysterious and often misunderstood by pet parents. Compared to dogs, cats are better at hiding their fears, and they make it harder for owners to determine the source of the behavior. However, you can study your pet’s body language for clues about their distress. Understanding what upsets your cat will help you calm them down and reduce future occurrences by avoiding the stressor.

When your cat growls or hisses at guests, your first reaction shouldn’t be to yell or chase the animal out of the room. While this may seem like a temporary solution to make your guest feel comfortable, it doesn’t do your cat any good and just scares them, potentially making things worse. It also does not address the cause of the aggression. Before labeling your cat as aggressive, you can examine why your cat may be acting unpleasantly towards strangers.


The 7 Potential Reasons Why a Cat Hisses and Growls at Strangers

1. Territorial Aggression

Like most animals, cats establish territories that may include the entire house or only sections of it. Although entire males can be more particular about their boundaries than females, both sexes can display aggression towards strangers or unfamiliar visitors. When a cat feels uncomfortable or threatened by a new presence in the home, they may respond by hissing, growling, or rarely attacking the stranger.

Some of the circumstances that can encourage more territorial aggression include:
  • A new pet in the home
  • A change in the environment like moving to a new residence
  • Returning home from a long trip
How to remedy the problem:

Create a place where your cat can hide when they feel uncomfortable. You can set up a cat condo or a cozy bed in a quieter area of the home that will serve as a refuge for your pet within their territory. Here, they should have their complete privacy and not be disturbed. Ask your guests to avoid approaching the cat or petting them until the cat becomes more accustomed to their presence and chooses to interact on their own.

cat hissing
Image By: yvonneschmu, Pixabay

2. Maternal Aggression

Females are protective mothers that will lash out at anyone who approaches their kittens. If your feline is usually calm and friendly towards all humans, they can still show aggression if raising their offspring. It can take 4 to 6 weeks for kittens to be weaned from their mother’s milk, and mothers may display aggression towards strangers until their kittens become more independent.

How to remedy the problem:

Keep the cat family in another room far away from the area where your guests congregate. Create a comfortable and noise-free environment for the animals and prevent strangers from approaching the kittens until the mother seems less protective of her children. You may have to wait a month or more for the mother to tolerate visitors near her family, but it would be best for strangers not to touch the kittens but just to observe them.

3. Fear Induced Aggression

When a cat is fearful of someone in your home, they may display a combination of defensive and offensive aggression. When cats show a defensive stance, they will flatten their ears, tuck their tail in, have their hackles up, or crouch with wide open eyes and large pupils. However, if the visitor does not go away and continues to irritate the animal, they may turn to offensive tactics such as hissing, growling, or staring at the person while moving closer.

How to remedy the problem:

Grabbing your cat or yelling can increase the fear and aggression and should be avoided, as the cat may turn to strike you. Ask your guest to join you in another room and allow your cat to calm down before approaching them. You can try and introduce your cat to the stranger in small steps by keeping the cat and visitor apart in subsequent visits and gradually decreasing the distance between them. Reward your pet with treats when they do not get upset when visitors enter your home. But also, respect your cat’s emotions and do not force any interactions they are not comfortable with.

angry cat hissing
Image by: Fang_Y_M, Pixabay

4. Pain Induced Aggression

Sudden aggression towards a visitor or family member is shocking to owners, especially when the cat is ordinarily sweet and good-natured towards all humans. A common cause of sudden aggression in cats is an illness, and pain can turn a lovable cat into a fearful and paranoid animal. Several medical problems, including trauma, arthritis, urinary tract disease, infections, and dental issues, can lead to aggression.

How to remedy the problem:

Your veterinarian can help you determine why your cat is in pain. A complete examination and additional tests may be required to diagnose your pet’s condition. When the illness is treated and the cat recovers, they should be more comfortable around strangers.

5. Redirected Aggression

Although it may seem like your pet is targeting a guest that they do not trust, the aggression could be related to another situation or animal that’s upsetting the cat. If a stranger approaches when your cat is staring out of the window at a bird or other animal in the yard, they can redirect their anger towards that person. The cat may see the person as someone who is interrupting their hunting prospects. A loud noise like a sonic boom or firework explosion may also upset the cat, and a stranger approaching when they’re scared may be met with hissing or striking. Cats may also be frustrated if they are teased by toys but not allowed to have them, so always make sure they have the chance to “catch” their toy and feel accomplished.

How to remedy the problem:

Different cats have varying prey drives, and some cats are more likely to act aggressively when their predatory nature is challenged and they cannot react to the stimuli, like seeing another cat or bird outside. Ask your friends to stay away from your pet when they’re staring at prey animals through a window and set up a cat bed or condo in a room your pet can use to escape loud noises. If your cat is getting frustrated watching through the window, pull the blind down to give them a break. Ensure there is plenty of indoor enrichment and toys, and play actively with your cat in order to stimulate them mentally and physically. If your cat has severe anxiety, talk to your veterinarian to see if your cat would benefit from pheromone diffusers or anti-anxiety medication.

a kitten hissing
Image by: Marlon Soares, Unsplash

6. Petting Induced Aggression

You may have noticed your cat’s attitude abruptly shifts when they’re being petted. Some cats will purr and roll around and then strike or growl at the person petting them. Petting-induced aggression is not entirely understood by veterinary behaviorists. However, some veterinarians speculate that cats become irritated by repetitive motions. If someone rubs the same area repeatedly, the cat may have had enough and decide to warn the petter with a hiss or strike from their paw. Although many cats enjoy petting, some merely tolerate it.

How to remedy the problem:

Watch your cat’s body language while being petted. The switch from lovable to grumpy may seem sudden, but you can look for signs the cat is becoming annoyed before they lash out. If the ears are pulled back and their eyes are partially dilated, they may be experiencing discomfort and signaling the petting should end. Every cat has a different tolerance for human contact, and you may have to ask your guest to limit how long they touch your pet.

7. Idiopathic Aggression

Aggression in felines is a complex subject that behaviorists and doctors have worked tirelessly to understand. Although the causes of deviant behavior are clearer, some aggressive acts are difficult to classify. When a veterinarian and a feline behaviorist have ruled out medical and behavioral problems, particularly redirected aggression, they may diagnose your pet with idiopathic aggression. That means that the cause of the aggression cannot be explained by the patient’s history or medical status.

How to remedy the problem:

If your cat’s aggression is unprovoked and out of control, you should visit a veterinary behaviorist. Unfortunately, many pet parents take their angry cats to shelters out of fear. Many cats are surrendered to shelters across the U.S. and the world each year, and oftentimes, this is related to behavioral issues and aggression. Getting down to the root cause of the issue with the professional help from your vet and a feline behaviorist is crucial. It may take time to find a way to successfully manage the issue, but a specialist may suggest relaxing supplements, increasing exercise and mental stimulation sessions, or rearranging your home to make the cat more relaxed.

a tabby mackerel cat hissing
Image by: strh, Pixabay


Tips for Preventing Escalating Aggression in Cats

We’ve touched on some of the methods of reducing feline aggression, but here are a few additional suggestions for handling an angry cat.

  • When your cat hisses at a visitor, ignore the behavior and calmly escort your guest into another room.
  • Avoid yelling or punishing the cat. Verbal or physical abuse is not acceptable in any instance and will only increase fear and may cause your cat to become more aloof and anxious.
  • Ask your friends not to approach your cat until they have seen them several times and feel more comfortable about them.
  • Ensure that your cat’s condo or bed is in a quiet area of the house.
  • Keep the litter box in a quiet room away from loud machinery.
  • Play games with your cat every day and ensure they get enough exercise while considering their age and health.
  • Feed your cat a well-balanced diet with premium cat food and fresh water.
  • Introduce new pets to your cat gradually. Keep the animals separated for the first few weeks and place their food bowl in separate rooms. Ensure each pet has their own privacy and resources, such as toys and beds.
  • Reward your kitty with a treat when they act friendly to a stranger that they once hissed at.
  • Visit the veterinarian at least twice a year to ensure your cat stays healthy and happy.



A grumpy cat is amusing to some people, but aggression is not a behavior you want to see in your pet. Cats are small creatures, but their sharp claws and fangs can cause considerable injuries to unsuspecting humans. Determining the reason for the behavior is a priority, but you cannot expect your pet to change overnight. There may also be a medical reason for your cat hissing or growling that should be ruled out by a veterinarian. 

Cats take longer to relax after a frightening occurrence than dogs, and it may take days or weeks for your cat to accept a new face in the house. However, following some of our tips, ensuring your cat is not painful or ill by taking them to the vet, and providing plenty of mental and physical stimulation and enrichment may help in keeping the animal relaxed and preventing injuries to your guests.

Featured Image Credit: Slava Dumchev, Shutterstock

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