I agree females until about 2 years the male somewhere between 3-4. I still use my grab method to stop biting. A little nip now and then is OK, but a hard bite is greeted with my thumb in the mouth and gently holding the lower jaw. As they relies that they are trapped they get a little scared. After doing this a couple of times they get the idea that it’s not a good idea too bite. If they are swiping or biting any one else I have become a really good shot with the water bottle. As I have said before we have bottles all around the house, a bout 8 of them