I would not recommend feeding a live gerbil. Gerbils WILL fight back, given the opportunity. I kept and bred gerbils as pets as a kid, and had a dog who was always really interested in the gerbils. One day I heard a crash, followed by the dog howling like someone was killing him. Ran into the room to find the gerbil cage knocked over, and the gerbil latched on to the dog's nose by his teeth.