Rats are emphatic to each other. And what about humans ?

Scientific American tells of another empathy research in animals which enforces the lessons of modern science: the qualities commonly defined as "uniquely human" are actually qualities animals and people share. This still isn't Doctor Dolittle's world, but we are coming closer...

According to a new study published in Science magazine, rats displayed repeated acts of empathy, helping peers escape a cage, even at the cost of having to share candies.

The experiment placed one rat in a cage and another outside it where it was able to open the cage and liberate its peer by trial and error. The rats displayed surprise and fear at first when they discovered their ability to open the door, but later on stopped displaying fear and repeated opening the door in occurring experiments, indicating they opened the door deliberately. The rats showed no interest in opening empty cages or cages containing rat-like toys.

Viewing that, researchers tried to make the decision harder, while learning about the strength of the empathy: two cages were introduced. One with a trapped rat, the other with chocolate (which turns out to be a favorite among rats, just as it is among humans). Most rats released the trapped rat and shared the chocolate.
Peggy Mason (one of the three researchers) told Scientific American: "In our lab we called it the 'chocolate versus pal' experiment...The rat could have put his butt in the opening of the cage containing chocolate to block the other guy, but he didn't. They were sharing food with their pals. In rat land, that is big—I was shocked." According to Mason,  sometimes the free rats placed the chocolate chips in front of or very near their recently released peers!

This experiment, strengthening past experiments which indicated reciprocal altruism among rats makes it clear: the golden rule of ethics, "Do unto others as you would have them do unto you", present in all human cultures, is probably present in all mammals. 

It might even be present in all animals, at least to a degree. 

Time and research will tell.

What remains to be understood regarding human empathy, is the complicated and intricate relationship between the demands of our biology and the demands of our developed morality, as expressed in religion, law and social norms. Clearly, seeing human societies, biological empathy is not enough.