A group of rats is called a mischief.

A mischief usually consists of many related rats living in the same area. They communicate using smells and high-pitched sounds that humans cannot hear. Researchers have found these sounds are similar to laughter when the rats play together.In 2011, scientists at the University of Chicago studied rat behavior. They placed one rat in a trap and let another rat roam free. The free rat worked hard to let its friend out of the trap. Even when the free rat was given chocolate, it chose to save its friend first and then share the treat.Rats also spend a lot of time cleaning each other. This is called allogrooming. It helps the rats stay healthy and keeps the group calm. This behavior lowers stress levels for every rat in the mischief.Rats are very cautious about new things in their environment. They often wait to see if another rat eats a new food before they try it themselves. This collective caution helps the whole group stay safe from poison or traps. Their memory and ability to learn paths are similar to the intelligence seen in dogs.