The Family Dog
An article from Doggone Safe at http://www.doggonesafe.com/Dog_bite_prevention_for_parents
Sometimes it is difficult for children to understand that the family dog may not always welcome their attention. It may seem hard to believe, but most bites to children are by the family dog or other dogs known to the child. Kids (and parents) assume that because the dog knows, likes or loves them that it won't bite them. Dogs don't think this way. A dog may snap or bite in annoyance because the child is bothering it in that moment, whether the dog loves the child or not.
Here is an example with which most kids can identify...
When you are home at night watching TV or reading a bedtime story you might like to sit on your Mom or Dad's knee or have them whisper "I love you" in your ear. However if you are out on the soccer field or at school with your friends or acting in the school play you might not want to sit on a parent's lap or have them run out in the middle of the game or the play to whisper in your ear. It's the same for dogs. If they are busy doing something, or interested in another dog or a squirrel, or they are tired they may not want to have attention from you that they might enjoy at other times.
A dog may indicate that it wants to be left alone by leaving the room, showing a half moon eye (see below), yawning or licking its chops when the kids are bothering it for weeks, months or even years before finally getting to the point that it feels it has no choice but to bite. Parents often tell us that the dog bit without warning, but there is always a warning. Many people simply do not recognize the warning signs, even though the dog has been exhibiting these for weeks, months or even years.
We are not saying that all signs of anxiety that we describe on the body language page indicate an impending bite. What we are saying is that the dog will tell you if it is uncomfortable in a situation with a child (or with you). As a parent and/or dog owner it is up to you to educate yourself and your children so that you all know what the dog might be feeling. Dogs give us a lot of love and joy and we know that you want your dog to be happy and to have a great relationship with the family. Learning about dog body language and emotion and developing empathy for dogs is a great way to help improve the relationship with your dog.
Read an excellent article about whether dogs bite "out of the blue". Realize that even the nicest dog can be pushed to the point of biting if multiple stressors come into play. Read an article that explains how this can happen.