Puppies are curious and energetic. They’re attentive and demanding too. There’s a lot you need to teach them and a lot of things they might do to vex you. For example, learning where and when to pee and poop? That’s a big hurdle! Learning appropriate interactions with humans and other dogs is a big step too. And then there’s biting.
Think about a puppy like you would a toddler, only on an accelerated schedule. Your puppy is getting a lot of teeth all at once — in fact their permanent teeth will mostly be in place by about six months of age. And, they’re still trying out all their unsocial behaviors like jumping and peeing and, of course, biting non-appropriate things (like hands and other dogs).
What your puppy needs, of course, is training in order to temper their natural urge to bite. This graphic offers some insights on how to help them.