Like humans, rats are not fans of any extreme temperatures, either hot or cold. Unlike humans, they have a far lower tolerance to heat than we do. Either end of the Fahrenheit / Celsius scale will a rat running for shelter, but if you had to choose a rat’s more favorable end of the thermometer, it would be cold. Because rats are by design a nocturnal creature, they tend to move about at night or in the very early morning hours. These are usually the coolest hours of the day. Having said that, it follows that the heat is more dangerous to rats than is the cold. Through countless generations, they have acclimated to being “hot-blooded” with a body temperature of about 99F.

This is one reason they are more comfortable being active when it is cooler, and because of this, as a species, rats do not have good tolerance to the heat. They are able to cope far better with the cold. Rats are unable to either sweat, or pant. In order to cool their naturally high body temperatures they have specialized blood vessels in their hairless tails that allow them send a larger blood flow there. Blood carries excess heat to the bare tail, the heat is radiated out into the surrounding air. This is why you often see a rat curled up hidden, except for its tail peeking out.

In the fall through the spring, rats are extremely noisy and active, running about their space and being vocal. In the heat of summer, you will notice a definite decline in rat activity, unless of course, they are enjoying the comforts of you AC!



Remember a rat is a “creature of the night”. As a rule, they do not even like sunlight. People who keep pet rats usually provide them with the coolest spot in the house for the summer. While many animals enjoy sunbathing, rats have nothing to gain from excessive heat, and can in fact die. At 85F a rat will be too warm, 90F it is uncomfortable, 100F puts the rat in great physical distress, and by 104F the rat will be dead.

This article is not advocating the use of either heat or cold in an attempt to control any rodent problem you might have, but more of a guide as to when to expect the most in rodent activity. Knowing the habits of any creature helps you to understand their thought processes and makes you better prepared to battle against an infestation in the future.

Read the How to get rid of rats page for helpful information and to learn more about Do rats like cold weather?

Do rats like cold weather?