When you think of an aggressive dog breed, a vision of a Rottweiler or German shepherd with their teeth prominently displayed may come to mind. Although these dogs have earned the reputation of being aggressive and hard to handle, the most aggressive dog breeds may not be your stereotypical muscle dogs. Rottweilers and German shepherds are more likely to be considered a threat in people's minds because of their size. What if you pump up a Pekingese, a dog breed that usually doesn't care for strangers, to the size of a Rottweiler? Changes are the Pekingese would be a force to be reckoned with. Here are some of the most aggressive dog breeds you may not have considered. Keep in mind these are only generalizations. There are gentle dogs of every breed.

The Dachshund

While most people won't feel the need to cross the street to avoid a Dachshund, maybe they should. Surprisingly, twenty percent of dachshunds have attempted to bite someone at one time or another and some regularly snap at their owners. In fact, in England the Dachshund has earned the reputation as being the most aggressive dog. Could it be their history of being bred to hunt badgers? Whatever the reason, you can sleep better at night knowing this little terror doesn't weigh a hundred pounds.

The Chihuahua

You wouldn't know it looking at Tinkerbell of the Taco Bell Chihuahua mascot, but this breed has a lot of spunk and isn't particularly fond of children. This high strung and excitable breed appears to do more than their share of nipping, snapping, and growling. The only saving grace is their teeth aren't very large.

The Jack Russell Terrier

This is another high strung, excitable dog that's full of energy and, sometimes, self importance. They have a tendency to display dominance behavior over other dogs and with their energetic nature; they can put on a good chase. Although stubborn, with good training, they can be energetic without manifesting serious aggressive tendencies.

The Chow Chow

Chows tend to be independent and somewhat antisocial, although they're usually fiercely loyal and protective of their owners. They have a reputation for being aggressive towards other animals, particularly cats. They're a great “one person” dog who can be counted upon to defend their master in almost any situation.

Although none of these dogs are as massive as the Rottweiler, they've each earned their reputation for being cranky and occasionally aggressive. It just goes to show you, sometimes it's the small ones you have to worry about.