Unexplained feline aggression by Anita Kelsey

When you have experienced aggression from your cat without much explanation it can be  very worrying and very frightening. Below are a few common causes of unexplained feline aggression although most cases do need an expert to help, so that the situation does not get worse. Feline aggression is one of the main reasons I am contacted. I am contacted on a regular basis to assist with unexplained feline aggression assessments for rescue centres as well as the RSPCA. Please contact me should you need help with this type of issue

unexplained feline aggression














Redirected aggression  in felines occurs when a cat encounters something unpleasant, prompting it to vent its displeasure through aggression towards nearby targets, such as humans or other cats in its environment. This aggression can manifest instantly or with a delay, potentially resulting in significant harm.

When a cat is in this heightened state, it’s crucial not to provoke it further. It’s advisable to remove oneself from the situation or guide the cat to a quiet space where it can calm down.

Understanding the underlying cause of the cat’s behavior requires the expertise of a cat behavior specialist. The source of the cat’s agitation may not be immediately apparent to the owner, especially if the outburst is a delayed response.

If this type of aggression is between cats that once got along, it can take many months to help break down memories of an attack and the fear/defensive response cycle.

If a cat owner become afraid of their cat it can elicit a cycle of fear coming from the owner and the cat wondering why the anxiety and fear is coming from them, making them even worse. The worst thing a cat guardian can do is show they are afraid of their cats, although it can be extremely difficult not to be afraid when aggression comes out of the blue.

Examples that could cause redirected aggression:

  1. Seeing a cat outside
  2. Hearing an unexpected noise
  3. Seeing a reflection in the mirror
  4. Hearing fireworks
  5. Loud argument in the home
  6. Unexpected visitors
  7. Another cat in the home scaring the cat
  8. Accident such as someone stepping on the cat’s tail

unexplained feline aggression








Play aggression. This is play that becomes focused on human limbs. It’s a natural action for cats to be predatory and also to become stimulated on prey items but when it’s guided onto human limbs it’s usually because a cat has no other outlets for this type of natural behavior. What follows is stimulation from the owners when swiping the feet or legs. They get stimulation from the reaction of owners, which is usually to move said limb about to get it out of the way of claws! The best way to combat this type of issue is to provide your cat with appropriate toys plus block off any areas where they jump out from under. A climber also is highly recommended as it gets your cat off from the floor and less likely to batt moving legs or feet. Having access to a garden, if possible, on your cat’s own terms, will also help as they can choose when to go outside as they please.

Examples that could cause play aggression:

  • Playing with cat, when young, with hands
  • Bored cat
  • Unstimulating territory
  • Lack of proper toys
  • Lack of training and guidance

Territorial aggression. As someone who cares for cats, I occasionally encounter situations where a cat becomes extremely aggressive in the absence of its owner, particularly when I enter their home to attend to them. This aggression can be intensified by the cat’s limited exposure to people other than its owner, causing any unfamiliar individuals, including myself, to be perceived as intruders. Handling a cat that hisses or displays aggressive behavior during feeding or litter changes can be daunting and stressful, not only for myself but also for the cat. Such situations can evoke feelings of unease and present challenges in providing proper care. Additionally, cats may experience separation anxiety and exhibit signs of fear and depression when their owner is away for an extended period, lasting longer than 24 hours. Territorial aggression is displayed with a cat blocking areas and hissing/growling and sometimes attacking visitors. Territorial aggression is also common between a new cat and a resident cat.

Examples that could cause territorial aggression:

  1. New cat introduced in the home
  2. Visitors in the home when cat doesn’t see many people
  3. Cat sitter in the home when guardians are away
  4. Feelings of insecurities or over ownership of territory (usually indoor only cats)

unexplained feline aggression












Pain aggression. This type of aggression will stand out because there will be no other explanation and may be connected to touching a part of the body. It usually occurs with other signs such as your cat acting out of character and or hiding away. It would be a type of aggression that isn’t so much an attack aggression, like -redirected aggression, but more an aggression shown if trying to touch a cat or pick up a cat or get near to a cat. cats have a high pain threshold so once they do show pain, you can be assured they are really going through the wars. If a cat perceives pain or discomfort (vets/groomers) that are likely to also show defensive posturing and will probably scratch and bite to get the desired outcome they want which is for the groomer or vet to stop.

Examples that could cause pain aggression:

  1. Cat unwell or injured which might not show or be understood
  2. Cat reacting aggressively to being touched
  3. Aggression totally out of character
  4. Cat reacting to an procedure at the vets

unexplained feline aggression









Defensive/fear aggression. This aggression would manifest when a cat is feeling under threat or cornered. We usually see this type of aggression in rescue centre situations, at the vets or groomers, if the cat is scared, or with feral cats. A defensive cat can cause a lot of harm and usually give out warning signs such as hissing when they want someone or something to back off/away. If the warnings are ignored a defensive cat will attack. They usually puff themselves up too if they want to show the upper hand and if they are ready to fight.

Examples that could cause defensive fear/ aggression:

  1. Cat feeling afraid or perceiving fear
  2. Cat cornered ready to lash out
  3. Cat ready to fight another cat
  4. Cat ready to defend itself from another animal/human
unexplained feline aggression
This cat is showing a fear response, low to the ground with flattened ears and wide eyes. This cat is likely to show a freeze response rather than attack.









Low petting aggression. 

This is an issue that causes a cat to become too aroused and conflicted with over stroking them. Cats with low petting aggression want to be stroked but then feel conflict with how it’s making them feel inside. The arousal leads to heightened sensitivity to conflict to aggression. It is best to stroke these cats just for a few seconds and then stop; being very aware of the body language they are giving off. Allow them mainly to do all the work, head butting you (sign of affection and placing scent on you) and allowing them to become relaxed without getting anxious over too much touching.

Examples that could cause low petting aggression:

  1. Cat being over stroked
  2. Cat getting unwanted attention
  3. Cat being picked up when it doesn’t want to be

unexplained feline aggression








Feline Hyperesthesia aggression. This is a little understood condition that usually manifests itself with tic like movements from a cat, skin rippling on the back and jaulty skin nibbling and over grooming in a manic like manor. According to https://www.vet.cornell.edu/ while some veterinarians feel that feline hyperesthesia is related to obsessive compulsive disorders, Dr. Alexander de Lahunta, emeritus professor at Cornell University College of Veterinary Medicine and a renowned pioneer in veterinary neurology, feels it could be representative of a seizure type problem. Feline Hyperesthesia can show moments of extreme aggression that are totally unpredictable and unexplained. Usually medication is used to manage this type of aggression. There is no cure for feline hyperesthesia and it is also hard for vets to diagnose.

Examples of Feline Hyperesthesia aggression.

  1. Aggression totally out of the blue / no reason for it


I hope this has helped a little.

Feline aggression is usually complex and each case needs a home visit and for me to meet the cats and see the territory.

My greatest reward is repairing relationships between cat owners and their pets as well as multi cat relationships.


unexplained feline aggressionAbout this author:

Anita Kelsey holds a first class honours degree in Feline Behaviour and Psychology (work based BA Hons) and runs a vet referral service dedicated strictly to the diagnosis and treatment of behaviour problems in cats. She is also a qualified cat groomer and specialises in grooming aggressive or phobic cats. Anita writes for Your Cat Magazine and is on their experts panel answering readers questions on cat grooming. She also advises on feline behaviour for the CFBA (Canine and Feline Behaviour) magazine as well as being a full member. Anita, a strong advocate of a vegan lifestyle, is based in London but consults all over the UK as well as international requests. She lives with her husband, a music producer, and one Norwegian Forest cat, Kiki.

Her first book ‘Claws. Confessions Of A Professional Cat Groomer‘ was published by John Blake in 2017 with her second book, Let’s Talk About Cats released on Amazon US and UK 2020. Her third book about cats will be announced this year and will be available to buy soon!

unexplained feline aggression