Why it’s so dangerous to leave your pet in the car

Most pet parents love their fur babies and would never do anything to harm them, but many don’t understand how quickly a parked car can heat up to temperatures that could endanger their pets.

Heatstroke, or heat exhaustion, happens when a pet is exposed to hot temperatures and can’t bring their body temperature down to normal levels. Excessive humidity, being in an enclosed space and a lack of water are all factors that can increase a pet’s risk of developing heatstroke.

Pets that are obese and brachycephalic breeds like Pug dogs, French Bulldogs, British Shorthair cats and Persian Longhair cats are more likely to suffer from heatstroke. Pets that are very young or old, pets with thick coats and those with pre-existing lung or heart conditions are also at risk.

Being left unattended in a car is a common cause of pet heatstroke. While most people understand that pets should never be left in a car for a long time, few appreciate just how hot the temperature inside a parked car can get – and how quickly.

Without cool air conditioning or the steady flow of fresh air as the car moves, a parked car heats up quickly even if it’s shaded and the windows are open. In the time it takes to buy a takeaway coffee, the temperature inside your car could reach dangerous levels.

On a 21°C day, the inside temperature of your car can reach 32°C after 10 minutes and 40°C after 30 minutes.

In the warmer spring, summer and autumn months, it’s best to never leave your pet in the car – even for a short time.

Signs of heatstroke

Thermoregulation is how your pet maintains a steady body temperature even when the surrounding temperature fluctuates. Pets lose most heat from their bodies through convection (cooler air moving over their body) and conduction (from lying or sitting on cool surfaces). Though some heat is lost through evaporation – sweating and panting, it’s not as effective.

If your pet is in an environment with shade, water and a good amount of airflow, they’ll be able to manage their body temperature. While ‘how hot is too hot’ will vary for different pets, there are several signs of heatstroke to look out for:

  • Rapid breathing and pulse
  • Panting and drooling
  • Red tongue and mouth
  • Vomiting and diarrhoea
  • Lethargy or stumbling around

Heatstroke can cause cardiac failure, renal failure, brain damage and liver and muscular damage. Its effects can be fatal.

If you’re worried your pet is suffering from heatstroke, it’s best to contact your vet as soon as possible. Take your pet to a cool, well-ventilated area and use a fan to blow cool air on them. Spraying or sponging cool or tepid (not cold) water can also help cool down your pet, but it’s important to note that you don’t want your pet to cool down too quickly. Your vet team can talk you through what to do before you arrive at the veterinary clinic.

What to do if you see a pet trapped in a hot car

Since 2018, leaving an animal trapped inside a car is an offence under the Animal Welfare Act. If you see a pet trapped inside a vehicle that looks like it’s suffering from heatstroke or stress, call the police, roadside assistance or your local animal care immediately.

  • Police 111
  • AA 0800 500 222 or *222 from mobile phones
  • SPCA 0800 77 22 69

Get the vehicle’s plate number and go to the nearest store or business to request an emergency announcement be made about a pet left in a hot car, then go back to the car and wait for police.

Don’t break into a car to rescue a pet – this could endanger you and the animal.

When it comes to heatstroke, prevention is best. Always make sure your pet has access to plenty of fresh, cool water and a shaded, well-ventilated area to hang out in. If you have your pet in the car with you and need to get out – even if it’s only for 10 minutes – take them with you.


Heat Stroke, Amy N. Breton, The New Zealand Veterinary Nurse (September 2014), accessed November 2022, https://www.nzvna.org.nz/site/nzvna/files/Quizzes/Heat%20Stroke.pdf

If you love them, don’t leave them!, SPCA (December 2019), accessed November 2022, https://www.spca.nz/news-and-events/news-article/dogsinhotcars


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