Chihuahua
Small
USA
Although some history exists in regards to dogs similar to the modern-day Chihuahua, the origins of Chihuahuas seem somewhat shrouded in mystery. Some claim the dog originated in Mexico during ancient times, while others say that Chihuahuas were developed in China. Some long-ago Chinese practices included breeding animals into miniaturized versions of their ancestors.
Chihuahua's are highly intelligent and quite nosy, they love to investigate. Their exercise area must be fenced securely. They do need a stimulating environment inside and outside, toys to play with, and company. When possible they like the companionship of another dog preferably of the same breed, as well as the company of its owner. To be shut in an empty house for hours on end with no companion is tortuous for any dog including a chihuahua. They are highly intelligent and have a high I.Q. (for a dog). With love and friendly discipline chis are eminently trainable. Taking time and trouble to train a chi will be very rewarding. It should easily master a vocabulary of commands like no, down, sit, quiet, out, come, bedtime and of course good dog or bad dog as appropriate. Fetch might prove more of a problem, they are not natural retrievers. They are just as likely to regard you with an expression that plainly says "you threw it, so you fetch it". Yes, chis do have a very independent streak.