One case involved an 18-day-old male infant attacked by a pit bull. The second case involved a 3-month-old male infant attacked by a Chow Chow and/or a Dachshund; and the third case involved an 18-day-old female infant attacked by a Labrador-pit bull mix. In all the cases, the victim was left in a mobile swing, unsupervised by an adult; and the attacking dog was a family pet. None of the dogs involved had prior histories of aggression. The authors report on the injuries that caused the deaths of the infants. Given that a mobile swing was involved in all the cases, the authors hypothesize that the motion of the swings provoked instinctual predatory aggression in the dogs, causing them to attack the moving infant in the swing. Regardless of the triggering mechanism, however, the unpredictability of dog behavior requires that young children be under the direct supervision of adults when they are in the presence of dogs. The literature review notes that dog-bite fatalities are rare, and major risk factors for dog-bite-related fatalities include the victim's age, location of the attack, the presence or absence of restraints, and the breed of the attacking dog. Most lethal attacks involve young children unable to defend themselves and family dogs that are not restrained. The top three dog breeds involved in fatal attacks are pit-bull-type dogs, rottweilers, and German shepherds. Other risk factors are a male dog and a male victim. Possible reasons for aggressive dog behavior are discussed. 2 figures and 17 references