Your giving them way too much credit here.
I caught one in a rat trap in my roof once and its mates came along and ate it. Ripped it apart full canabilsation with guts and blood strewn from one end of the roof to the other. Smart?? Yeah smart enough to grab a free easy feed on their downed comrade!
Its in between.
Just like people, rats 'personalities' vary, some don't give a **** about others. Sometimes they will finish off a severely wounded/ill mate... or consume the bodies of the dead.
But on the whole, rats are social and intelligent and do aid each other in survival as a matter of instinct... there is strength in numbers.
However I think this article does go a bit too far... I have not once in my entire time keeping rats witness one willingly "share" food with anything other than juvenile individuals. In fact, if you watch them with a tasty morsel, they horde it, they try to steal from each other and desperately try to keep their treats safe from other rats.
The rat releasing the other rat was probably mostly out of curiosity at what the other rat is doing in this tube. The fact that occasionally they opened the traps even when there were no rats inside shows its not specific to a trapped rat.
Seems like dodgy findings to me anyway. They are social animals, no doubt. I just think the idea of them being highly empathetic and sharing is a bit far fetched.
However they show about as much empathy as humans do. You choose whether thats saying they have enormous empathy or almost none at all. lol I know which I meant by it
Looking at the way we treat each other and the world around us... yeaaah...