That's what I've heard and that's what I've done in the past. However, when I tried the scented rat a few days back, I did a lot to get the scent of mouse in the enclosure. I even rubbed the mouse around the area where she normally feeds. I could tell the the BP was eager to eat as she spent 2 days ready to pounce. I had already been having some reservations about using warm water to warm up the pup, so once I heard of the hairdryer trick, I decided to take the risk.