Pets die in hot cars Leaving a pet in a car, even for a short time, can be fatal. Help Save the Animals is urging you not to take your pet for that much wanted ' ride this summer, j The temperature inside a car is ! sometimes up to 40 degrees hotter i than it is outdoors. Because pets can't perspire, heat stroke usually sets in causing death within minutes. mi-nutes. Help Save the Animals urges you to be kind to your pet this summer sum-mer and leave him home.