As we approach summer and warmer temperatures in New Hampshire, we start to see instances of people leaving their dogs in cars without the AC running. The hottest, most sultry days of summer, are the 40 days beginning July 3 and ending August 11. As we transition into summer, it is important for pet owners to be mindful of pet safety in cars.
Heatstroke in Dogs
One of the primary causes of heatstroke in dogs is being left unattended in a parked vehicle on a hot day. Even leaving a car in the shade with the windows cracked open is not enough to keep the interior of the car cool enough to sustain life, human or animal. A car left on with the AC running can run out of gas or the AC can stop working. An unfortunate incident resulted in the death of a dog this summer when the owner told police she left her dog in the car with the motor running and the air-conditioning on high while she went to visit someone — and lost track of time.
Scholars at the Stanford University School of Medicine performed a study in which they investigated the rate at which the interior temperature of a parked car increased during sunny days of temperatures between 72 and 96 degrees Fahrenheit.
Their findings demonstrated that the temperature inside a car can increase by 40 degrees Fahrenheit on average over the course of 60 minutes, irrespective of the ambient temperature. The researchers also found that 80% of the observed increase in temperature occurred during the first 30 minutes.
As you can see from the chart below, it only takes 10 minutes on an 85 degree (F) day for the interior of a car to reach 104 degrees. Now imagine wearing a fur coat in that car!
Estimated Vehicle Interior Air Temperature vs. Elapsed Time
Elapsed Time (minutes)
Outside Air Temperature (°F)
Dogs have a higher body temp than we do and they can’t cool down as efficiently as we can. Dogs are designed more for insulation from the cold than cooling down in the heat.
Humans have sweat glands all over their bodies. A dog’s sweat glands are confined to their nose and the pads of their feet. A dog that is heating up can only normalize its body temperature through panting, which doesn’t get the job done under extreme conditions. In a very short period of time, an overheated dog can suffer critical damage to their brain, heart, liver and nervous system.
Symptoms of overheating in dogs include:
Elevated body temperature
Increased pulse & heartbeat
Vomiting, bloody diarrhea
Bright or dark red tongue and gums
If your dog’s body temperature gets to 109°F or higher, heatstroke is the result. The cells of the body rapidly start to die. The brain swells, causing seizures. Lack of blood supply to the GI tract causes ulcers. Dehydration leads to irreversible kidney damage. All these catastrophic events take place within a matter of minutes.
Helping a dog who is hyperthermic
If your dog becomes hyperthermic or overheated, or you find a dog that is, there are some things you can do to help stop the process until the animal can be seen by a Veterinarian:
Remove the dog from the car immediately and place them in the shade or somewhere air-conditioned. A fan can also be very helpful.
Try to cool the animal down as soon as possible with cool (not cold) water. If the dog is not close to running water, have someone go soak a towel or cloth in cool water and apply it to the dog’s “underarms” and inner thighs, where the fur is usually thinner and large blood vessels run close to the surface.
If the dog is conscious, attempt to get him to drink small amounts of cool water. Letting the dog drink too much at once will most likely result in vomiting and increase their dehydration.
Get the dog to the Vet as soon as possible, even if he/she looks to be recovering okay. Vital signs and bloodwork should be done to evaluate any major organ damage.
Is there a safe temperature to leave a dog in a car?
There is no safe temperature to leave a dog in a car! According to the American Veterinary Medical Association (AVMA), studies have shown that cracking a window changes these figures very little. A parked car with the windows cracked heats up at almost the exact same rate as a car with the windows rolled up, putting pets in serious danger.
Leaving the car motor running is also a bad idea. An unrestrained dog can accidentally put the car in gear, cars can run out of gas, and AC units can fail. A Google search will uncover numerous stories of unnecessary deaths due to leaving dogs unattended in cars.
Is it illegal in NH to leave your dog in a parked car?
In the State of NH, the law cites that it shall be cruelty to confine an animal in a motor vehicle or other enclosed space in which the temperature is either so high or so low as to cause serious harm to the animal. Our state only considers it a misdemeanor as set forth in RSA 644:8 to leave your dog in a hot car. The laws are not strong enough that is why your help is needed!
If you see a dog in a hot car, your first instinct will most likely be to help. Unfortunately, in NH, there are no laws to protect civilians like there are in Massachusetts. In MA, a person who removes an animal from a motor vehicle, under certain circumstances, is immune from criminal or civil liability resulting from removal.
In NH, only a law enforcement officer, or agent of a licensed humane organization, may take action necessary to rescue a confined animal endangered by extreme temperatures and to remove the threat of further serious harm.
How you can help
As a concerned citizen and pet lover, your quick actions could save the life of a dog, or other domestic pet, in distress. Here is how you can help:
Remain calm: the pet needs your help and the only way you can be helpful is to remain calm.
Assess the situation: has the pet owner been gone for only a few seconds (i.e. post office) or several minutes (i.e. grocery store, mall, etc.).
Collect information: collect critical information that will be needed to locate and rescue a pet, including the town/city you are in, description and location of the vehicle, license plate number, and condition and type of pet.
Call 911 or local dispatch: if you do not know your local police department’s dispatch number, or the pet is in serious distress, call 911.
Stay by the car and monitor the pet: this way the responding police officer can easily find you and collect any additional information needed to rescue the distressed pet.
Grab a copy of our Pets in Hot Cars seasonal take action guide for your refrigerator.