How do you know if your cat has a fever? Known as pyrexia, cat fever can be defined as a higher than a normal body temperature in felines. The normal body temperature for felines is between 38.1°C to 39.2°C. Cats are considered to have a fever if their body temperature is above 39.7°C, according to VCA Hospitals.
Causes Of A Fever In Cats
According to PetMD, fever in cats usually results when the immune system is activated by conditions such as:

- Infection: Bacterial, fungal or viral infections of a milder nature.
- Cancer: Tumors tend to affect aging cats more than younger ones.
- Injury from trauma
- Side effects of certain medications: Antihistamines, certain antibiotics, interferons.
- Immune-mediated disorders: Common example is lupus. Lupus is an autoimmune disease that occurs when the body’s immune system becomes hyper-defensive, attacking the normal cells, tissues and organs of its own body.
Signs Of A Fever In Cats
The primary symptom associated with fever in felines is a body temperature above 39.7°C. There are other symptoms that can indicate the presence of a fever, including:
- Lethargy
- Dehydration
- Reluctance to move
- Loss of appetite
- Pain and tenderness when touched (hyperalgesia)
- Shivering
- Hunched over appearance
- Increased breathing (hyperpnea)
How Can I Tell If My Cat Has A Fever?
The only way to check if your cat has a fever is to take her temperature. A fever in cats occurs when temperatures rise above 39.7°C. Although fevers may be helpful in fighting disease, a fever higher than 41.11°C can damage organs. If your cat does have a fever, bring her to your veterinarian as soon as possible.
Here are the steps to take your cat’s rectal temperature:
- Prepare thermometer, KY jelly or other water-based lubricant and towel.
- If you are using a mercury thermometer, shake it with a quick flick of the wrist until the mercury is below 94 degrees (34.44°C). Then, lubricate the thermometer with water-based lubricant. A digital thermometer is a good option as well – it typically gives a faster result than a mercury thermometer.
- Stand your cat on the counter and hold her securely with your left arm like a football, with her tail towards the front of your body. Wrap her in a towel with her butt end protruding if necessary.
- Lift her tail and insert the thermometer slowly and carefully into the rectum, located just below the base of the tail. Be sure to only insert the thermometer about 1 inch (2.54cm) and hold in place for two minutes.
- Remove the thermometer and read the result.