Dogs are very much like children and need to be educated about how to behave properly and what behaviors are unacceptable. If a puppy isn't trained, then problem behaviors will persist into adulthood and worsen. Not only will the behaviors themselves increase in frequency, but an adult dog's actions can be much more dangerous than the actions of a small puppy. One of the dog behaviors that can get out of hand if not curtailed early on is biting.
No dog behavior is inherently "bad." Dog behavior is the result of both the natural forces that shaped wolf pack behavior and the selective breeding humans performed in order to create breeds suitable for specific jobs. Add to that the fact that dogs do not have hands to explore the world; for dogs, then, their mouths become both a means of communication and a means to explore the world. Puppies also use their teeth when playing, especially with their littermates. Play-fighting is a very important part of puppy socialization; littermates and mothers have the very important role of teaching a puppy to not play too roughly and hurt with their biting. When you bring a puppy home, you have to continue that lesson and make sure you do not encourage your puppy's biting.
While all puppies and dogs have the instinct to use their mouths, there are some breeds that are more prone to biting because of their breeding. Breeds that were used as herding dogs, such as the Norwegian Elkhound, are especially prone to biting and nipping (herding dogs often bite and nip at the heels of their flock when herding). It may not seem like a serious issue when your puppy bites a lot, but imagine a very large and muscular adult Norwegian Elkhound with biting problems. This is why puppies should be trained from the moment they join your family that biting will not be tolerated.
If your Norwegian Elkhound is an adult dog with biting problems, you'll have a bit more work to do. You'll first have to figure out why and in what situations your dog resorts to biting. Elkhounds will bite for a number of reasons, including out of fear, happiness and dislike; essentially, they are trying to communicate something to either the humans or dogs around them. Take note of the situation in which the biting occurs. If your dog bites because he is playing, make sure you stop playing with him until he learns that biting is unacceptable. Since Elkhounds were also used as guard dogs, they often are wary of new situations and new people and so could feel the need to bite out of defense; Norwegian Elkhounds do not get along well with dogs of the same sex and so could feel threatened if found in close proximity of a dog of the same sex. Proper socialization can take care of these problems. You should also try to introduce your Elkhound to new environments frequently, initially for only short periods of time; an obedience class with a small number of dogs may be a good idea. Praise your dog profusely if he remains calm when presented with new surroundings.