While not all studies agree on which dog breeds are most likely to bite, several breeds come up repeatedly:
Pit bulls, which some studies show are more than 20 percent of bites. The New York City Housing Authority bans them
Chihuahuas, which are known for dominant, jealous, and aggressive tendencies
Dachshunds, whose aggressive behavior is often overlooked by owners because of their small size
Jack Russell terriers, which were bred to hunt foxes
German Shepherds, which are high energy and suffer from separation anxiety
While breed can contribute to the propensity to bite, the most important factor is the level of training the dog has received.