Did you know that rodents laugh when tickled? It's true. They can also feel each other's pain (or at least see it in each other's faces) and can even tell the difference between a Picasso and a Renoir.
And a new study shows that male mice break out into song when they want to woo the ladies! (Ordinarily, the freaky serenade is too high-pitched to be heard by humans, but in the video above the pitch has been lowered to make it audible.)