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How To Take A Dogs Temperature With An Infrared Thermometer

If you need to take your dog’s temperature, you are going to need to know how to use an infrared thermometer. And then you’ll need to know how to read the results – what should your dog’s temperature be, even? How do you know if your dog is running a fever, or is too cold? And then, what do you do in either context? Well, here’s everything you’ll want to know.

So, how do you take a dog’s temperature with an infrared thermometer? To take a dog’s temperature with an infrared thermometer, place a protective cover on the end of the probe. Insert the probe into the ear canal (keep it in a horizontal position). Keep it there until it beeps, then remove it and take the reading.

Sounds simple, right?

But there is certainly a little more to it.

Particularly if you want to respond in the right way once you get the results.

And there are other ways to take a dogs temperature too, you know.

So continue reading to find out exactly what you need to do. Before, during and after infrared thermometer use!

What Should A Dogs Temperature Be?

Your dog’s temperature should be between 99.5 to 102.5 degrees F (37.5 to 39.1 degrees C).

Temperatures Outside The Normal Range

If your dog’s temperature goes above 103 degrees F (39.4 degrees C), your dog has a fever, and you’ll want to call your vet.

Likewise, if your dog’s temperature goes below 99 degrees F (37.2 degrees C), your dog has caught a chill, and you’ll want to contact your vet.

Why Does A Normal Temperature For Dogs Vary So Much?

You might be surprised that the normal temperature for dogs can vary within a range of three degrees F (or 2.2 degrees C).

There are several reasons why a dog’s temperature can vary slightly.

Where You Take Your Dogs Temperature

If you take your dog’s temperature from the inside of his ear (an auricular reading), you can get a slightly higher reading than if you had taken his temperature under his armpit (an axillary reading).

If you take your dog’s temperature using a rectal thermometer, the reading is likely to be in the middle range (lower than auricular readings but higher than axillary readings).

When You Take Your Dogs Temperature

If your dog has just exercised, his body temperature is likely to be slightly higher than if he’s lying peacefully on the ground.

In addition, a dog’s temperature will often naturally rise slightly at nighttime.

How To Determine What’s Normal For Your Dog

The best way to know the normal temperature for your dog is to take his temperature at varying times of day over a few days.

You’ll soon see a predictable pattern that will leave you well-equipped to know where your dog’s normal temperature falls within the range described above.

How To Take A Dogs Temperature With An Infrared Thermometer – Step by Step

You can use an infrared thermometer to take your dog’s temperature by the auricular method (inserting it into his ear).

First, it’s worth knowing that although auricular thermometers are fairly accurate, research shows that the most accurate way of taking your dog’s temperature is rectally.

However, your dog prefers something inserted into his ear rather than into his anus.

It can be painful for you and your dog as he suffers the indignity of something in his butt.

It’s worth doing your research, as it can be challenging to find a good auricular thermometer for dogs (most on the market are repackaged human thermometers).

Good ones are available but can be expensive as they are veterinary-grade instruments.

We’ll go into other methods of taking your dog’s temperature below, but for now, let’s look at how you use your infrared thermometer for best results.

Step One: Know Your Dogs Ear Anatomy

Understanding the anatomy of your dog’s ear is essential before inserting a thermometer into it.

You’ll need to ensure you are placing the thermometer correctly to get the best possible reading, as an infrared thermometer works by bouncing a beam of light off your dog’s ear drum.

Your dog’s ear canal is L-shaped. In other words:

  1. The first section of your dog’s ear canal is called the vertical ear canal. It makes a 90-degree turn towards the bottom of your dog’s skull
  2. The second section is the horizontal ear canal,  the second 90-degree turn that ends at the ear drum.

When you insert the thermometer, you must go in, down, and in again. The probe must go into the horizontal portion of the ear canal.

Step Two: Use A Protective Covering

Now that you know how to insert the thermometer, you’ll need to place a protective cover on the end of the probe.

Step Three: Insert The Thermometer

Next, sit next to your dog and make sure he’s calm.

Stroke him gently or use something else to keep him calm while you insert the thermometer into his ear.

Step Four: Hold It In Place

Hold the thermometer steady and wait for it to beep before withdrawing it.

Keep your dog calm and ensure he doesn’t move so you can get an accurate reading.

Step Five: Clean The Thermometer

Once the thermometer has beeped and you’ve got the reading, remove it gently (bearing in mind those 90-degree turns).

Discard the protective cover, clean the thermometer according to the manufacturer’s instructions, and wash your hands.

What To Do If Your Dog Has A High Temperature

If your dog has a high temperature, it’s always a good idea to call your vet. Your dog could be running a fever because he’s fighting off an infection or an inflammation. A fever could also be a sign of something more serious. In some cases, though, you might want to monitor him at home for a few hours.

When To Monitor Your Dog At Home

If your dog’s temperature is under 103 degrees F (39.4 degrees C), you can probably monitor your dog at home for up to 24 hours. Minor fevers aren’t necessarily dangerous.

However, if the fever lasts for more than a day or your dog’s temperature is higher, it’s time to go to the vet.

When To See Your Vet

As we’ve said above, if your dog’s temperature is 103 degrees F (39.4 degrees C) for over 24 hours, it’s time to see your vet. Call your vet to tell them what’s going on.

If your dog’s temperature is anything higher, you need to see your vet urgently.

Temperatures of 106 degrees F (41.1 degrees C) can be fatal, as your dog’s internal organs could collapse or suffer permanent damage.

Other Things To Do

What You Can Do Yourself

Your vet may instruct you to do a few things immediately to help lower your dog’s temperature:

  • Be sure to help keep your dog hydrated by offering small amounts of water
  • Help him cool down by applying a damp, cool cloth to his ears and paw pads. These areas radiate a lot of heat, so by applying cool water, you are using evaporation to help your dog cool down
  • Apply some rubbing alcohol to your dog’s paw pads (not his ears). Some vets say because rubbing alcohol evaporates faster than water, it can help cool down your dog more efficiently
  • Place a fan directly opposite your dog

What Not to Do

No matter how worried you may be about your dog:

  • Never give aspirin, ibuprofen, or other home medications to your dog. Aspirin could lower the effectiveness of the medication that your vet will administer. Ibuprofen and similar medications are toxic to dogs and can be fatal
  • When cooling down your dog, don’t apply anything ice-cold, as this could cause your dog to go into shock

What Your Vet Will Do

If your dog is too weak to take in water, your vet will probably administer fluids with an IV and anti-inflammatory medication.

Your vet may also carry out blood tests to determine the cause of the fever if there is no evident injury or other condition.

You might not be able to find out what caused the fever, as it can be a myriad of things that are sometimes difficult to spot, even with blood tests.

The main thing is to help him recover by keeping him well-hydrated and comfortable, and the medication plus other treatments will do their job to help his immune system fight off the problem.

Common Causes of a High Temperature

Here are some common causes of a high temperature that are worth knowing about:

  • Respiratory infections
  • A fungal, bacterial, or viral infection
  • Urinary tract infections
  • Infected wounds or abscesses (such as a tooth infection)
  • Heat stroke
  • Pancreatitis
  • Cancer
  • Immune system diseases
  • A recent vaccination
  • Tick-borne diseases
  • Eating something toxic (plants, food, etc.)

Out of the above possible causes, infections and viruses are the most common.

The fever is your dog’s way of killing off the virus or bacteria.

Viruses and bacteria can only live within a small temperature range, which correlates to your dog’s normal body temperature.

Therefore, the pathogens start struggling to stay alive when your dog’s temperature rises.

What To Do If Your Dog Has a Low Temperature

If your dog’s temperature is 98 to 99 degrees F (36.7 to 37.2 degrees C), you can monitor him at home and try to raise his body temperature yourself. If your dog’s temperature is below 98 degrees F (36.7 degrees C), get him to the vet or emergency service for pets immediately.

What To Do Yourself

To raise your dog’s body temperature, try these methods:

  • Warm up blankets in the dryer or on a radiator as quickly as you can and wrap them around your dog
  • Place a hot water bottle in a towel and hold it against your dog’s stomach. Be sure to wrap the water bottle in a towel so that you don’t burn your dog
  • Give your dog some warm fluids to drink (such as bone broth or similar)
  • Help your dog to stay still, as excessive movements can cause him to lose body heat
  • Take your dog’s temperature every ten minutes. Once it’s above 100 degrees F (37.8 degrees C), remove the water bottle but keep your dog wrapped in blankets in a warm room

Note: Watch your dog at all times. If he wants to get away from the heat source, let him. You don’t want him to get too hot. You might see a slight drop in temperature when you first warm up your dog, which is normal. The cold blood near the surface of his skin will mix with the warmer blood that’s deeper inside your dog’s body. His temperature should stabilize quickly, but if it doesn’t, get him to the vet urgently.

What Your Vet Will Do

When your dog has regained his normal body temperature and seems to have recovered, schedule a visit to the vet.

You want to make sure he hasn’t suffered any long-term damage to his heart or other organs.

Your vet will do a urinalysis and check your dog’s blood.

Other Ways To Take A Dogs Temperature

If you aren’t ready to invest in an effective infrared thermometer, there are other ways to take your dog’s temperature. You can use the axillary or rectal method.

The Axillary Method (Under the Armpit)

Taking your dog’s temperature under his armpit is a less invasive and easier (although less accurate) method.

This method is best used if your dog really won’t accept a rectal thermometer or if you can’t get an infrared thermometer.

Here’s how to use this method:

  1. Get your dog to sit calmly. Kneel next to him with a clean thermometer. You can let him sniff the thermometer first to help him satisfy his curiosity and let him know that it isn’t anything dangerous.
  2. Insert the thermometer gently between your dog’s chest and his front leg. Keep your dog as immobile and as calm as possible. You can try rubbing his ear to keep him quiet and happy.
  3. Once the thermometer has beeped, or you know the right amount of time has passed (according to the manufacturer’s instructions), remove it. Note the reading and let your dog do his thing.
  4. Wash the thermometer as well as your hands. All done!

Note: You’ll usually need to add one degree F (0.5 degrees C) to the reading for an estimate of your dog’s temperature. This method only gives an approximate reading, so if you have doubts or your dog shows signs of a fever, go to your vet for an accurate reading.

The Rectal Method

Although dogs really don’t like this method, it is one of the cheapest and most accurate ways to take your dog’s temperature without a veterinary-grade infrared thermometer.

You can opt for a rectal thermometer with a flexible tip, as these are more comfortable for dogs once they’re inserted.

However, a flexible tip can be more difficult to insert into tight rectums.

Here’s how to use the rectal method:

  1. Rinse the thermometer to remove any dust. You don’t need to sterilize it, as it isn’t going into a sterile environment
  2. Have your dog in a place where he usually feels calm and comfortable. Enlist someone to keep your dog calm while kneeling or sitting beside them. If you’re alone, get your dog to lie down on his side
  3. Apply a small amount of petroleum jelly (Vaseline) to the tip of the thermometer
  4. Hold the thermometer in one hand and gently lift your dog’s tail with the other
  5. Gently slide the thermometer into your dog’s rectum using a slow, twisting motion. Make sure you don’t insert it too far – one to three inches is enough. The bigger your dog, the deeper the thermometer needs to go, so check with your vet first if you aren’t sure how deep to go
  6. Keep your dog calm and relaxed while the thermometer adjusts to the temperature of your dog’s rectum. Check how long this needs to be according to the manufacturer’s instructions (usually about 2 minutes)
  7. Pull out the thermometer and let your dog get up and run off in shame (this is completely normal!)
  8. Praise your dog, possibly with a treat, for being a good dog
  9. Take note of the reading (you may need to wipe the thermometer first)
  10. Sterilize the thermometer by soaking it for a few minutes in some rubbing alcohol

Note: Make sure you don’t insert the thermometer into your dog’s feces, as this won’t be an accurate reading. You can avoid this problem by gently moving the thermometer along the wall of the rectum when you insert it.

Additional Tips

Here are some extra tips for taking your dog’s temperature, no matter the method:

  • Label your dog’s thermometer. You don’t want curious humans using it!
  • Don’t use glass thermometers, as these could break and cause injury. Glass thermometers often take a bit longer to get a reading, and most dogs won’t tolerate them for long, so you want the thermometer to work as quickly as possible. Fast, digital thermometers are your best bet.
  • If your dog’s temperature is unusually high, try not to panic or stress, as your dog will sense your emotional state. You don’t want your dog to be upset in addition to having a fever.
  • If your dog becomes aggressive during the temperature-taking process, stop immediately. A sick dog could growl or snap at you, so look for other fever symptoms and get him to the vet.


Measuring your dogs temperature with an infrared thermometer is pretty straight forward once you know how.

There are certainly best practices to follow, though.

And one quick thing before I let you go – if you’re buying a new thermometer from scratch, check the packaging and documentation.

Some brands have slightly different operational instructions.

So do perhaps consider those too!

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