"This suggests that knowing that soaking is distressing enhances the rats' motivation to help their cage mate," says Nobuya Sato of Kwansei Gakuin University in Japan.  Rats have more heart than you might think. One rat was made to swim for its life in the pool, with another being in a cage adjacent to it. Evolutionary behaviour 
 
 Sato's team also showed that rats learned to open the door to free a wet rat more quickly if they themselves had previously been soaked. It is possible, says Sato, that these rats opened the chamber quicker because they had already observed how the door mechanism works when they were soaked. Journal reference: Animal Cognition, DOI: 10.1007/s10071-015-0872-2 
 
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– Rats may not have the best reputation, but a new study suggests that they're actually pretty good citizens. Researchers found that if a rat is in distress in water, another will save it, according to a post in Science Daily. Researchers put one rat in a pool of water and another in a dry area, with the two separated by a door. The dry rats soon learned that they could let the other rat through the door, thereby rescuing it—and they hurried to open the door only if the other animal seemed to be in real distress. What's more, rats who knew what it was like to be soaked, having been through it themselves, learned about the rescue mechanism faster than others. "This suggests that knowing that soaking is distressing enhances the rats' motivation to help their cage mate," a researcher tells New Scientist. "We think this comes from empathy." In fact, those in the experiment seemed to care enough about their struggling brethren to forgo chocolate for them. Given the option of saving a fellow rat or getting a snack, they tended to opt for the rescue first. Previous studies have also pointed to empathy in rats, but further work is needed to be sure, researchers say. (Elephants, meanwhile, have been seen to console each other.)