Tickle That Rat

Truly seen on TV: There was this grey-bearded serious scientist, who spent two years tickling rats on their bellies - and found out they liked it. And there was this biologist, who recorded elephant sounds in Africa, and played them to elephants in a European zoo - and found out they were intrigued.
No, this was not a poorly known Monty Python sketch, this was a serious TV report on animal's feelings...
It's been 150 years that the Origin of the Species has been published, and still experts in the field are surprised to see that other mammals behave and feel in a way very similar to us...
Poor Darwin.