Maybe it isn't so bad to be called a rat after all. Nobuya Sato and his research team from Japan's Kwansei Gakuin University have published work in the journal Animal Cognition that shows that rats will rescue each other from drowning. Rats which have already survived a close call with drowning are even more likely to help.

Sato's team worked with rats to prove the existence of prosocial behavior in rats of the same species. Past research already established that rats will help each other escape from cages. Sato and his team wanted to take this research a step further, placing both trapped and potential "rescuing" rats in jeopardy from drowning.

The team found that when one rat had to swim for its life and could only access a safe, dry cage with the assistance of a cagemate, the caged rats rapidly learned to save the rats in water, who were in distress. In fact, these rats only opened the door when the swimming rat was distressed-only when the action was important for the survival of the swimming rat.

Perhaps unsurprisingly, the researchers also found that the rates dislike being soaked with water. However, the truly remarkable finding in this area was that rats who had previously been immersed were much faster than rates without a near drowning experience when it came to determining how to save the distressed rats.

Most interestingly, the team ran a series of experiments in which the "savior" rat had to choose between helping the distressed rat in water and getting a food treat for themselves. For the most part, rats chose to help the distressed rats before taking the treat.

In other words, the team concluded that rats place more value on saving others than obtaining a food reward. The rats can understand and share in the emotional state of their cagemates: they experience a kind of empathy.

"Our findings suggest that rats can behave prosocially and that helper rats may be motivated by empathy-like feelings towards their distressed cagemate," Sato says. His premise is that studies of prosocial behavior, like the empathy in rats seen here, are essential to the comprehension of the evolutionary aspects and neurological basis of prosocial behavior.