How do I know if my cat has a fever?

A cat's normal temperature is between 38°C and 39°C, we class it as a fever if the cat's temperature is 39.5°C or higher. A cat's body temperature can rise slightly if it is nervous or stressed, which is good to keep in mind when taking its temperature. It is also important to know that a low body temperature can indicate that the cat is seriously ill.

A vet will often take a cat's temperature as part of the clinical examination if there is a suspected illness.

“Fever is a common symptom of illness and acts as the body's defence mechanism against, for example, viral infections. When body temperature rises, an unfavourable environment is created for viruses to multiply.”

Symptoms of fever in cats

The symptoms of fever in cats can vary, but common signs may be that the cat:

Is off colour
Is lethargic or tired
Has a reduced appetite
Is breathing fas
Has bright pink or red gums
Behaves differently, e.g., becomes more withdrawn

Causes of fever in cats

Fever in cats can be caused by:

Viral diseases such as cat flu

Bacterial infections such as an infected bite wound

Inflammation such as pancreatitis

Autoimmune diseases

Tumors

A reaction to medication

Good to know

It is not considered reliable to feel the nose, paws, or ears to determine if your cat has a fever. The only way to know for sure is to measure the rectal temperature. However, keep in mind that cats are often not very fond of this so it may be a good idea to get help to hold your cat. See below for tips on taking a temperature.

How to take your cat's temperature

Preparation:

Beware that cats can bite and scratch and these injuries can sometimes be serious. You should do your own risk assessment and only attempt to take your cat’s temperature if you feel confident doing so.

Ask someone to help you and wrap the cat in a blanket or towel if possible. Do not hold the cat too tightly. Hold the cat gently and close to your body. Place one hand around the cat and one in front so it cannot run away.

3 steps to take your cat's temperature

Use a digital rectal thermometer with some lubricant, petroleum jelly, or ointment on the tip.
Take the temperature in the rectum. This gives the most reliable reading.
Release the cat gently after taking the temperature.

If the cat becomes scared or angry, contact your vet for help.

Tip: To help assess if your cat has a fever, it is good to know your cat's normal body temperature, as it can vary between individual cat’s. Do this when the cat is healthy, preferably after resting or when the cat is calm. Repeat the procedure over a few days, at about the same time each day, to get a good reference point.

What can you do yourself?

If you suspect your cat has a fever, then the first thing would be to find out for sure by taking its temperature. If your cat has a slightly elevated body temperature but otherwise seems well, then you can often keep your cat under extra supervision. Make sure the cat is drinking, eating, and doing its business as usual. Pay attention to other signs such as changes in breathing patterns or problems urinating. Keep in mind that it is not always easy to see if a cat is affected by pain or a fever.

When do you need to see a vet?

You should contact your vet if your cat has a fever or shows symptoms of a fever, especially if:

The fever exceeds 39.5°C.
The fever lasts longer than 24 hours.
If the cat has hypothermia, i.e. a lower temperature than normal
The cat shows signs of illness, such as difficulty breathing, vomiting, or diarrhea.
The cat appears to be in pain, is lethargic, or shows other signs of not feeling well.