Hyperthermia, leaving pets in cars and what Denton laws say residents can do about it.

Man sitting poolside on a chair made of pool noodles. Text reads "Brace Yourselves, Summer Is Coming"

We are barely halfway into May and Denton is already expected to see temperatures in the mid 90’s this weekend. With the heat brings summer fun in the sun, but it is also brings many dangers with it. This is the time where veterinary practices all around the country start to prepare for heat stroke season. As someone who worked in veterinary medicine for over a decade, this is one of the scariest times of the year. I was at Walmart the other day, putting my groceries in my trunk, when I heard a sound that made my heart stop and my “spidey senses” go into full effect. I heard a dog barking their head off inside a hot locked car while their owner was inside shopping. I immediately called Animal Control and wait patiently for the owner to return. Thankfully, he returned and we had a somewhat nice conversation about why he shouldn't leave his pet in a car, but these situations do not always end well for everyone involved.

Most people haven’t had the experiences I have had when it comes to heat stroke, so it’s hard for people to realize just how dangerous it is. But as someone who has seen the suffering, from someone who has had animals die in my arms as I am trying desperately to save their lives, I beg of you, please stop leaving animals in hot cars. Please help educate people you know to stop leaving pets in cars and outside when it is too hot. Please help advocate for these pets.

Here are a couple videos that you may or may not have seen showing just how hot it gets in cars. They do a wonderful job at illustrating just how hot cars can get in a matter of minutes.

From my years in vet med, I can tell you most people don’t mean to do things that will hurt their pet. Most people simply don’t know better. It was my job to educate them then, and I will continue to do so for as long as I can. I dedicated my life to animal welfare, and even if I am no longer in the trenches placing IV catheters on dehydrated, overheated, panting (sometimes seizing) animals while my coworkers start other cooling measures, it is still my duty to do what I can to educate.

Tragedy is Preventable

A dog can begin to suffer from heat exhaustion once temperatures reach 83 degrees F. So basically, from here on out in Texas, we should all be on high alert. Although normal values for dogs vary slightly, it usually is accepted that body temperatures above 103° F are abnormal. When a dog’s core temperature approaches 106° F, heat stroke can quickly become fatal.

When dogs are hot, they begin to pant and drool. Other signs of heat exhaustion include vomiting, weakness, collapse and seizures.

Brachycephalic (short snouted) dog breeds with such as boxers, pugs, Shar-Peis, Boston terriers, Brussels griffons, mastiffs, chow-chows, bulldogs, French bulldogs, Shih Tzus, Staffordshire terriers, Lhasa apsos, and spaniels are more susceptible to heat stroke. In other words, they can fall victim to heat exhaustion at a faster rate than dog breeds with a longer snout.

I remember a long time ago rushing to the clinic I worked at to help out of of our really good clients. A client that always went above and beyond for her furbabies. She was at Dog Days (back when it was in the middle of summer) and her poor bulldog got overheated. They even had little pools for the dogs to play in, but this Texas summer heat was too much for the dog. The dog was fine one second and in need of help the next. It can be hard for people to know how hot is too hot for a pet, but I always err on the side of caution.  

Other risk factors include but are not limited to:

  • Previous history of heat-related disease

  • Age extremes (very young, very old)

  • Heat intolerance due to poor acclimatization to the environment (such as a heavy coated dog in a hot geographical location)

  • Obesity

  • Poor heart/lung conditioning

  • Underlying heart/lung disease

  • Increased levels of thyroid hormone (hyperthyroidism)

  • Thick hair coat

  • Dehydration, insufficient water intake, restricted access to water

  • Hyperthermia (Heat Stroke) can lead to multiple organ dysfunction.Symptoms include:

  • Panting

  • Dehydration

  • Excessive drooling

  • Increased body temperature - above 103° F (39° C)

  • Reddened gums and moist tissues of the body

  • Production of only small amounts of urine or no urine

  • Sudden kidney failure

  • Rapid heart rate

  • Irregular heart beats

  • Shock

  • Stoppage of the heart and breathing

  • Fluid build-up in the lungs; sudden breathing distress

  • Blood-clotting disorder(s)

  • Vomiting blood

  • Passage of blood in the bowel movement or stool

  • Black, tarry stools

  • Small, pinpoint areas of bleeding

  • Generalized inflammatory response syndrome

  • Disease characterized by the breakdown of red-muscle tissue

  • Death of liver cells

  • Changes in mental status

  • Seizures

  • Muscle tremors

  • Wobbly, uncoordinated or drunken gait or movement

  • Unconsciousness in which the dog cannot be stimulated to be awakened


1. If possible, while you are starting cooling measures, have someone call your veterinarian and let them know you are on your way. If they are not open call the Denton County Animal Emergency Room (940) 271-1200 and let them know you are on the way. Heat Stroke and Heat Stress are EMERGENCY situations and need to be addressed as soon as possible.  We do NOT recommend that you wait for until the next morning to take your pet in.

2. Start cooling measures by gradually lower his body temperature by sprinkling cool water on him. Do not soak him in cool or cold water because his temperature could drop too low. If their temperature drops too low too fast they risk going into shock.

3. Place cool, wet towels over the back of the neck, in the armpits, and in the groin area and paws. 

4. You may offer fresh, cool water if your dog is alert and wants to drink. Do not force your pet to drink.

Heat and Humidity are a Deadly Combination for Dogs

Humidity is also a contributing factor to heat stroke/heat exhaustion in dogs.

Humidity increases the heat index; for example, a relatively cool 75 degree day with 75 percent humidity can feel like a 150 degree day to a dog in a fur coat. It’s a deadly combination. It's best to exercise dogs early in the morning or in the evening and avoid taking dogs with you in a car in the case that you may have to leave them waiting for you for any period of time.

Hot Temperatures Inside a Car

The temperature inside a car — even with the windows rolled down — can quickly rise an additional 20 degrees within the first 10 minutes. Within five minutes, the temperature inside your car can rise another 10 degrees, and so forth. By then, it's too hot for your dog and heat exhaustion has set in. Within minutes, your dog could suffer heat stroke and die.

Infographic: It's Too Hot To Leave Your Pet In The Car

How to help a pet left in a hot car

Take down the car's make, model and license plate number. If there are businesses nearby, notify their managers or security guards and ask them to make an announcement to find the car's owner. Many people are unaware of the danger of leaving pets in hot cars and will quickly return to their vehicle once they are alerted to the situation.

If the owner can't be found, call the non-emergency number of the Denton police (940) 349-8181 or animal control (940) 349-7594 and wait by the car for them to arrive. Good Samaritans in Denton, TX can NOT legally remove animals from cars under any certain circumstances.

United States map showing information about Good Samaritan laws

If you would like to see laws in Denton change please contact your local city council member. To find out who represents you at state and federal level, click here. This will provide you with contact information and you can talk to them about your concerns. 

There is only a snippet of information in the City of Denton Municipal Ordinances that talks about leaving animals in cars:

Sec. 6-12. - Animal care generally.

(2) It shall be unlawful for any person to intentionally or knowingly confine or allow to be confined any animal in a motor vehicle or trailer under such conditions or for such periods of time as may endanger the health or well-being of the animal due to heat, lack of food or water or any other circumstances which might cause suffering, disability or death. An animal control officer who reasonably believes that an animal is in a motor vehicle or trailer under such circumstances is authorized to enter the vehicle to remove the animal and transport the animal to the animal control center.

When I asked Paul O’Neill, Denton’s Animal Services Supervisor, about the city ordinances and if weather was a factor at all, this was his response: 

“If the animal is still in the vehicle when we get there then an officer has the authority to remove it. I am not aware of any Good Samaritan laws and would always caution damaging someone else’s property to remove an animal as you never know how the animal owner might react. The ordinance does not depend on the weather. I do like to be on scene when one of the officers removes the animal just in case the owner gets ugly but I don’t have to be. People can contact us at 940-349-7594 or the non-emergency dispatch number 940-349-8181."

Ways to help - Information from The Humane Society of the United States

  • Get informed: Learn your town's and state's laws about leaving pets in hot cars. An increasing amount of states prohibit leavings pets in hot cars, and some grant immunity to good Samaritans who must rescue pets in visible distress.

  • Be ready to call for help: Gather essential telephone numbers and have them on hand. You’ll want to have your local animal control agency's number and the police department's non-emergency number so you can quickly report the situation. Keep these numbers in your purse, your car's glove compartment or programmed into your phone.

  • Spread the word: Distribute The Humane Society of the United States hot car flyer, which spells out the dangers of leaving pets in parked cars. (Order them in bulk from animalsheltering.org.) Watch and share their retro video on the issue. Also share guidelines with your local law enforcement officials for how to investigate hot car-related deaths.

  • Get involved: Ask local store managers, shopping malls, restaurants and other businesses to post signs asking customers not to leave their pets in their cars while shopping or dining. A huge part of the solution to this problem is raising awareness.

  • Speak up: If your town or state doesn't have a law prohibiting leaving pets in parked cars, contact your local representatives or attend a town hall meeting to start lobbying for one. Learn the basics about advocating for animals with our activist toolkit.










Kiara Helgesen