…but rats are more like people than you might think:
Now may be as good a time as any to say that I am puzzled by people (or rats, for that matter) who like to be tickled. When I was growing up with an older brother, tickling was a reliable form of torture, and I was the torturee. The laughter that ensued was not happy-laughter.
But the rats appear to seek it out. Are they actually masochists?
[Hat tip: Althouse.]