Small breed dogs look so harmless and cute they have been mistaken for fashion accessories. But in that toy-sized body is an actual dog with all the usual canine qualities, perhaps more concentrated. And dogs need to be trained.

Untrained dogs are worse than a nuisance; they nip and bite and attack other dogs and humans The danger posed by larger breeds is in the damage they can do with their bite. Smaller dogs however, are in many ways more dangerous. Owners of aggressively territorial small dogs often don't take them seriously. These dogs are more likely to bite and less likely to be trained appropriately.

Chihuahuas, Dachshunds and Jack Russell Terriers were found to be the three most aggressive dog breeds, according to a University of Pennsylvania study published in 2008, Animal Behavior Science. This study used a survey of thousands of dog owners as well as experts in various breeds from American Kennel Club groups. Small dogs were identified by both groups to be more aggressive, territorial and likely to bite.

According to the Center for Disease Control, victims of dog bites in the U.S. are mostly children (over 60%); most of these bites were from the family dog Children are more likely to be bitten on or near the face than other dog bite victims. Small dog teeth are sharp. They can pierce skin easily.

Small dogs are often the cause of falls, as found in a 2009 study. People trip on their pets and fall, resulting in injury requiring medical treatment, roughly 25,000 times per year in the U.S, according to the CDC. Small dogs pose a much bigger problem in falls than the more easily seen larger breeds.

The answer to dog behavior problems lies in proper training and discipline. Dogs should not be treated as human babies or as toys. No matter how small, they need to learn not to rush the door when someone enters.