My boys have learned not to bite from me giving them a light tap/nudge and saying "No Bite" a couple of times. Now all I have to say is "No Bite" and they'll back off. I just wish I could get it to work with each other so I could reunite them in the same pen. Dawn and the Boys, Moka, BrownyBoy, and always in our hearts, Frankie (RIP 01/16/05)