Good call nighttrain......makes good sense. I've also come to the conclusion that they don't see that well for starters (clear eye not cloudy). It's almost like they use 2 senses to decide what something is. If they don't get both...it's not a mouse. My BP will pass over a thawed mouse if that mouse cools down....He obviously smells it but passes clean over it. If I heat the mouse back up...he will snap it up. Even if I don't shake it and its laying in his feeding cage. So a cooled down ,motionless mouse is pretty much invisible to my BP. A warm motionless mouse....he sees it.