A healthy adult cat’s normal body temperature is about 100.5–102.5°F (38.1–39.2°C), a little higher than ours. A temperature outside this range can be a sign that something is wrong. Here’s how to recognize a fever or a low temperature, how to check your cat’s temperature and when to call the vet.
Each cat’s normal temperature varies slightly, and it can rise a little with excitement, stress (for example, at the vet) or after exercise. Newborn kittens can’t regulate their body temperature well: in the first week of life, their temperature is lower, around 95–99°F (35–37°C), and gradually rises to adult levels by about four weeks of age. That’s why newborn kittens need a warm nest and their mother.
Signs That Your Cat May Have a Fever
A fever is often a sign that the body is fighting an infection or inflammation. It can also be caused by injuries, some medications, poisoning and other illnesses. Signs that your cat may have a fever include:
- loss of appetite, or refusing even favorite treats;
- lethargy, weakness and sleeping more;
- hiding and not wanting to play;
- fast heart rate or breathing;
- shivering;
- not grooming;
- vomiting or diarrhea, depending on the cause.
A warm, dry nose is not a reliable sign of fever. A cat’s nose can be warm and dry after sleeping or lying in the sun, and cool and wet even when it’s ill. The only way to know your cat’s temperature is to measure it.
Signs of a Low Body Temperature
A low temperature (hypothermia) can be just as dangerous as a fever. It can happen after exposure to cold, after anesthesia or with serious illness, shock or poisoning. Signs include shivering, cold ears and paws, lethargy, weakness and, in severe cases, slow breathing and collapse.
How to Take Your Cat’s Temperature
Most cats dislike having their temperature taken, and some will struggle. If your cat is very stressed or seems seriously ill, don’t try: go straight to the vet. If you’d like to be able to do it at home, ask your vet or vet nurse to show you how first.
The most accurate method is a rectal temperature, using a digital thermometer. Never use a glass mercury thermometer, which can break.
- Ask a helper to hold your cat gently but securely, or wrap your cat in a towel with its tail end out.
- Put a disposable cover on the thermometer, if you have one, and lubricate the tip with petroleum jelly or a water-based lubricant.
- Gently lift the tail and slowly insert the tip of the thermometer about 1/2 to 1 inch (1–2 cm) into the rectum. Never force it.
- Hold it in place until it beeps, usually within about 10 to 60 seconds, then gently remove it and read the result.
- Clean the thermometer afterward with soap and water or an alcohol wipe, and give your cat a treat.
Ear thermometers designed for pets can be used, but they’re less accurate, especially if the cat has an ear problem. Non-contact infrared thermometers aren’t reliable for measuring a cat’s body temperature, because the fur gets in the way.
When to Call the Vet
- Above 103°F (39.4°C): call your vet for advice, especially if your cat seems unwell.
- Above 104°F (40°C): contact your vet the same day.
- Above 105°F (40.5°C): this is an emergency. Go to a vet immediately. A very high temperature can be caused by heatstroke.
- Below 99°F (37.2°C): contact your vet urgently, and keep your cat warm on the way.
- Any temperature change in a kitten, a senior cat or a cat with health problems, or a fever that lasts more than a day, also needs a vet check.
Even without a thermometer, take your cat to the vet if it stops eating for more than a day, is very lethargic, or shows any of the signs above.
What to Do While You Wait for the Vet
Because a fever has many possible causes, your vet needs to find the cause and choose the right treatment. In the meantime:
- keep your cat in a quiet, comfortable room at a moderate temperature;
- make sure fresh water is always within easy reach, and offer it often, but don’t force your cat to drink;
- if your cat has a low temperature, keep it warm with blankets and a wrapped hot water bottle (not too hot), leaving room for it to move away from the heat;
- if your cat may be overheated, follow our heatstroke advice and go to the vet immediately.
Never give your cat fever reducers or painkillers made for people. Acetaminophen (paracetamol), ibuprofen and aspirin are toxic to cats and can be fatal. Don’t use ice packs on the skin, alcohol or vodka rubs, or cold baths either: they can be dangerous. Only give medication your vet has prescribed.
