The Dangers of Leaving Fido in a Hot Car

A black and white dog travels in a car

If we find the scorching summer temperatures unbearable outside of our cars, imagine how our furry friends feel when trapped inside. Dog fatalities from extreme heat in cars are avoidable and all-too common. Although leaving your pet in the car while you run a few errands may seem harmless, dogs can suffer from heatstroke in a matter of minutes, even if parked in the shade with the windows cracked.

“One study in the Journal of Pediatrics showed that cars parked in the sun showed an average of 40 degrees increase in internal temperature,” said Dr. James Barr, assistant professor at the Texas A&M College of Veterinary Medicine & Biomedical Sciences.  “This means, in 100 degree temperature, the car could reach 140 degrees.”

Although rolling the car windows down may seem like a workable solution, this is not the case, even if you only plan on leaving your dog in the car for a short period of time. Exposure to extreme heat for less than 20 minutes can still cause internal damage and be extremely harmful in the long run.

“That same study in the Journal of Pediatrics showed that the rate of temperature rise was slower if the car window was rolled down, but still remarkably dangerous and reached the same levels after 60 minutes,” said Barr. “So just rolling the window down is not sufficient.”

When humans overheat we sweat, and as the sweat dries it takes excess heat with it. Our four-legged friends only perspire around their paws, which is not enough to cool the body, and pant to rid themselves of excess heat. While this is efficient in controlling their body heat, it is of extremely limited effectiveness in high humidity or when in close quarters, such as a car.

“The body’s internal temperature rises when the gain of heat outpaces the ability to dissipate heat,” said Barr. “When locked in a car, body temperatures reach dangerous levels and organ damage can occur.”

While letting Fido tag along on your grocery store run during cooler temperatures is safer, keep in mind that temperatures inside of the car can still rise 40 degrees above the outside temperature. “This means that the car temperature can reach 115 degrees when the temperature is 75 degrees outside,” said Barr.

Additionally, keep in mind that some states even have laws deeming it illegal to leave an animal in a confined vehicle, as well as numerous local ordinances prohibiting this. Even without a specific state or local law, this action could still constitute cruelty under some circumstances, and you may ultimately lose custody of the animal in question.

“Also be especially cautious if your pet has a medical condition,” said Barr. “Respiratory, cardiac, and neurologic conditions may all impair the pet’s ability to dissipate heat, so it is especially important to take precautions.”

If you must travel somewhere with your pet during the summer, make sure they have access to plenty of water and proper ventilation and that the temperature they are kept in is reasonably low. Fatalities from heat stroke occur far too often, and our furry friends are relying on us to keep them out of harm’s way.

Pet Talk is a service of the College of Veterinary Medicine & Biomedical Sciences, Texas A&M University. Stories can be viewed on the Web at Suggestions for future topics may be directed to

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