"In a study published Dec. 7 in Science, Mason and University of Chicago psychologists Jean Decety and Inbal Ben-Ami Bartal describe their rat empathy-testing apparatus: An enclosure into which pairs of rats were placed, with one roaming free and the other restrained inside a plastic tube. It could only be opened from the outside, which is exactly what the free rats did — again and again and again, seemingly in response to their trapped companions’ distress."
This looks to me like activity of mirror neurons, which I read about in Ramachandran's book, The Tell-Tale Brain. It makes sense to me that animals would share anatomical structures, like eyes, or in this case, wads of neuronal networks. Not that we all fine-tune them in the same way. I envy birds' ability to fly!