According to recent studies, rats are not the disgusting, filthy and greedy creatures that most of us believe them to be. In fact, they demonstrate compassion, the desire to help their furry friends.
In repeated tests, rats freed another trapped rat in a cage, even when chocolate treats were offered as a tempting distraction. Twenty-three of the 30 rats opened the trap by pushing in a door. In some cases, the free rat took the chocolate out of the container, but did not eat it. Then it would free the other rat and share the food. Females were much more consistent with their empathy than males. All of them freed their trapped friend while 17 of the 24 males did.
It seems that empathy is not limited to humans and primates, after all. You might want to think twice about calling someone a dirty rat next time!