When dogs bite it is not unusual for the people involved in the incident to be shocked and to feel that the behaviour came “out of the blue”. Owners will often report that their dog has always been “fine” with visitors or with children when they report an incident in which a bite occurs. Veterinary practices can also find themselves taken aback when a canine patient bites. So is it true that canine bites come without warning or are there ways in which these behaviours can be predicted? The most important implication of this question is whether dog bites can be prevented. After all, if they are truly happening without warning prevention strategies are unlikely to be successful and dog bites will continue to occur and to take people by surprise. The good news is that biting without warning is unusual and if it does occur there has usually been a history which explains the lack of warning signals. Education both within the veterinary profession and within the dog owning public is necessary in order to improve detection of the warning signals and increase the potential for successful dog bite prevention initiatives, both locally and on a global scale.