How to tell if your dog has a fever (with or without a thermometer)

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Fevers are a scary thing, especially when they involve our furry friends! While we know what to do when one of our human loved ones has a fever, dogs are different and can be a bit trickier.

How do you tell when your dog has a fever with a thermometer? And if you don’t have one, how do you tell if your dog has a fever without a thermometer?

When does your dog’s fever warrant a trip to the vet? Whether you suspect that your pet has a fever currently or you are preparing in case of a future emergency, you’ve come to the right place. 

Learning About Your Dog’s Body Temperature 

If you are here to learn more about fevers in dogs, the first step is to learn about their normal body temperatures.

While humans have a body temperature that ranges from 97.6 to about 99.6 Fahrenheit, dogs tend to run much hotter.

In fact, the body temperature of dogs on a normal day can fall from 101 to 102.5 Fahrenheit! Anything above 103 degrees Fahrenheit for a dog is considered a fever, and anything over 106 is dangerous. 

Like humans, dogs have different body temperatures. Some run colder, and some run a lot hotter. What may be abnormal for your dog could be perfectly normal for the dog next door.

The best way to be prepared in case of a fever is to know your dog’s normal body temperature.

You can do this by taking their temperature regularly for a few days, making sure to take it at different times of the day and before, during, and even way after activity. This will give you a good solid average to work off of. 

How to Tell If Your Dog Has a Fever With a Thermometer

The most accurate way to check your dog’s temperature is through a rectal thermometer.

To take their temperature, lubricate the thermometer using some sort of water-soluble lubricant or petroleum and then insert the thermometer carefully after lifting their tail up.

It’s best to have another person assist you with this, as it’s difficult to do alone and your dog may be more temperamental than normal due to them not feeling well. 

Another option is an ear thermometer, but keep in mind that ear infections are one cause of a fever and if you insert a thermometer into an infected ear it’s going to cause pain for your dog.

Still, this is a less invasive way to figure out if your dog has a fever. Simply slide the thermometer into their ear until the temperature registers. 

If your dog is aggressive or won’t let you take their temperature, it is best to consult a vet for help. Don’t risk hurting yourself or your pet, and don’t let your dog go too long with an unknown high fever! 

How to Tell If Your Dog Has a Fever Without a Thermometer

You may have heard the age-old telltale sign of a dog’s fever is a hot, dry nose. While this sometimes works, it’s not always accurate.

That being said, if your dog always has a cool wet nose and you notice one that is dry and hot, it may be an indication that you need to check their temperature to be safe. 

Like humans, dogs show us that they have fevers based on the way that they act. Fevers don’t make anyone feel good, so there are a lot of signs that you can watch out for that are good indicators of your dog having something else going on.

If your dog has been acting weird or sick, it’s possible that they have a fever. Some signs to look out for are:

  • Runny nose
  • Decreased energy
  • Lethargy
  • Lack of appetite
  • Warm nose
  • Warm ears
  • Coughing 
  • Vomiting
  • Red eyes
  • Glassy eyes
  • Shivering 
  • Panting 

Most of these symptoms will go away once their fever passes. If your dog is exhibiting serious symptoms like lethargy for a long time, vomiting, shivering, or panting, they need medical attention immediately. These are emergency signs and should be taken seriously by any pet owner. 

When Is My Dog’s Fever an Emergency?

If your dog’s fever is 106 or over, they definitely need to be seen by an emergency vet immediately.

At this temperature, damage is being done to their organs and if their body temperature continues to be that hot, it can cause severe irreversible damage or even death. 

If your dog’s fever is under 106, you can attempt to comfort them and help to lower their fever. Just remember to take their temperature regularly.

That way you’ll ensure that it is not rising and be mindful of lethargic dog signs that indicate they need to be seen by a vet.

If your dog isn’t eating or drinking, they need to go to the vet to avoid dehydration which will make things severely worse. And once again, if they start panting, vomiting, or even shivering, they need to go to the vet.  

What Can Cause a Dog to Have a Fever?

There are a lot of reasons why a dog may have a fever. Some common causes include:

  • Any sort of viral infection
  • Ear infection
  • Fungal infections
  • Bacterial infections
  • Infected bites, scratches, cuts, etc. 
  • Ingestion of toxic/poisonous materials like plants, human medication, foods, etc. 
  • Tooth infection
  • Urinary tract infection

It’s important to note that some fevers can’t be explained easily. These are referred to as FUO, or fever of unknown origin. FUO can be caused by deeper-rooted issues like cancer, immune diseases, etc. 

It’s important to always keep a close eye on your dog and their behaviors so that you can give that information to your vet in case of emergency.

Don’t purchase toxic plants or ensure that they are in a secured plant cabinet or up high. Conceal and lock up medications at all times.

Do not drop human food on the floor and stay educated about the kinds of foods that are toxic to animals.

Being on alert and knowing where the things are that your dog could get into and ensuring that they are locked up and out of reach at all times is one of the best things you can do to prevent fever or illness in your dog. 

The vet will want to know medical history as well as any symptoms that your dog has, so be sure to take note of any strange behaviors. These may be the key to a proper diagnosis and treatment. 

Knowledge and Prevention is Key 

While some things that cause fevers are unpredictable and cannot be prevented, in many cases things like ingesting toxic materials can be prevented by ensuring that anything that could make your dog sick is locked up and out of reach.

Fevers and any other illness in our pets can be extremely scary. But knowledge is the most powerful tool that we have to ensure that we have the resources to get them help when they need it!

Knowing their regular body temperature and having a thermometer on hand is vital in case of an emergency. 

Remember, if your dog’s fever goes above 106 at any time or they experience any dangerous or concerning symptoms they need to be seen by a vet immediately! 

Do you have any tips or tricks to keep dogs calm while taking their temperature? Do you have a favorite thermometer brand to use while taking your dog’s temperature?

Let us know in the comments and please like and share this article with other dog owners!

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Lisemaine is a dog lover. She currently owns a Frenchie and enjoys working with and training her. She'll share her best tips with you to keep your dog happy, healthy, and active.


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