Chihuahuas take their name from the Mexican state of Chihuahua, and the AKC registered its first one in 1904. They're among the smallest dogs in the world, usually 3 to 9 pounds, with an apple-shaped head, large upright ears and either a smooth or long coat in nearly any color. Pet Chihuahuas often weigh more than the show standard allows, so a sturdier dog is common.
The personality is big for the size: alert, devoted and often wary of strangers. Many bond hard to one or two people and bark at new sounds. In Berkeley, that means calm introductions on busy sidewalks and gentle handling at home. Chihuahuas live 12 to 16 years, so adopting one is a long commitment, and adult Chihuahuas vary widely in age and temperament.