Chihuahua

First discovered in Mexico, the Chihuahua is best known for being the smallest dog breed in the world. Extremely loyal to its owner, the breed has recently become a popular culture icon in the United States, most notably Paris Hilton's Chihuahua, Tinkerbell.
While the Chihuahua is reserved towards strangers, it is friendly with pets and other household dogs. The dog may also try to act protective, but this boldness is generally displayed as barking and is, therefore, not very effective as a guard dog.

This dog is so small, you can actually fit THREE a cup!!!

   

                                                            Even cats aren't afraid of them!!