It is quite normal for puppies to mouth people. What you need to teach him is that it hurts by yelping or shouting "ouch" and turn away from him. He will learn that if he bites too hard, he will not get attention from you. That's how dogs teach each other.
You should also make sure that he gets to play with lots of other well socialised dogs, they are much better at teaching this stuff than we ever are... ;)
Here's an article that explains it all in a bit more detail:
Puppy BitingPuppy biting will stop probably within a month or two. Has he started teething yet? Once they have their new teeth, most stop biting quite so much.
Re chewing everything (which again is perfectly normal), provide him with as much chewable stuff as possible. Provide a plain old card board box, fill it crunched up newspaper and hide treats and toys in there for him to find. You can also give him stuffed kongs... in fact, I would feed him for example breakfast in a stuffed and frozen kong (soak food, stuff it in kong, put it in freezer, then give it frozen - takes them ages to get it out and involves lots of chewing). There are also nylabones which many dogs like too.
What do you feed him? I would make sure that you use a food which is free from artificial additives as they can make some dogs a bit hyper, and at five months old, I would also put him on an adult food, not puppy anymore as the high protein contents makes them grow too quickly (not good for their joints) and can make them a bit hyper too.
Vera :)
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