When I was in high school I had a pet rat. I remember being surprised by how easily trainable he seemed to be – I got him to jump and climb on command without even giving any kind of reward. "Jump, rat!" I would say, and he would crouch and look around and then jump several feet, from my hand to various other surfaces.
The rats in this video are much better trained.
[daily log (1100 pm): walking, 5 km]