Are rats capable of empathy?
In 2011, neuroscientist Peggy Mason and her student Inbal Ben-Ami Bartal at the University of Chicago published a study in the journal Science that suggested they are.
They placed one rat inside a narrow, clear tube with a door that could only be opened from the outside. Another rat, a cage-mate, was free in the arena.
The free rat seemed upset by its trapped companion. Over several days, most of the free rats learned to open the door. They did it again and again, quickly and on purpose, and set their friend free.
They did not do the same for an empty tube or a tube with a toy rat.
Then the researchers made it harder. They gave the free rat a choice between a tube with chocolate chips and the tube holding its trapped friend. Many rats opened both. And they often shared the chocolate.
It was strong evidence that empathy may run deep in the animal kingdom.