Famous Dog Trainer Dr. Ian Dunbar of Sirius Puppy Training recommends a multi-step approach to teaching bite inhibition in puppies. He explains that puppies learn through play with litter mates and others to bite gently. If they bite a playmate too hard, the other puppies will cry or yelp, and possibly stop playing if the bite is severe enough. To recreate this learning process with a new puppy in a human home he advises to first teach the puppy to bite softly before teaching them to stop biting on command, and finally teach that puppies are not allowed to start biting without permission.
The first step is to teach the puppy that hard biting is not allowed. For this step you have to set your puppy up to bite. Since biting is a natural part of puppy play, this isn’t usually difficult. During a play session, when your puppy bites, even if it doesn’t really hurt, pretend that it does. Yell, “Ouch!” and take your hand away, or stop playing for a few seconds. If the puppy calms down, great, you can go back to playing and continue the training. If the puppy continues to try to come and bite, you may need to put a more serious break in the play by stepping out of the room for a moment. Over time the puppy will learn that humans are very fragile and they will become gentler so they get to keep playing. Eventually, you will yell your “Ouch!” even when the puppy barely puts any pressure into the bite at all, teaching them that any pressure cannot be tolerated by humans.
Consistency is important in puppy training, so make sure all members of the household who will be playing with the puppy understand this process, so the puppy learns to be gentle with all humans, not just the one doing their training.
Once the puppy has learned to not put any pressure into their play bites, they are ready for the next step in Dunbar’s plan which it to teach the ‘Off’ command. This is taught by hand feeding kibble with the command ‘Off’ being used when they come to take the kibble from you. Then make them wait a few seconds before letting them have it. For a video example of how this would work, see: https://www.youtube.com/watch?v=chJqKoYeIk0
The last step in the process is to teach that the puppy is never allowed to bite, or mouth at humans until they are invited. Dunbar suggests in an ideal situation, beginning bite inhibition training before the puppy is 3 months old, and discontinuing any mouthing by 6 to 8 months of age. At this age the puppy’s jaws are not as strong as they will be as an adult and the training will go smoother. However, bite inhibition is an important skill to teach dogs, and should still be taught even outside this ideal training window.