DNA studies suggest that native American dogs entered North America from Siberia roughly 10,000 years ago, and were then isolated for some 9,000 years until the arrival of the first Europeans; these pre-contact dog… See more

Chihuahuas are the smallest breed recognized by some kennel clubs. Current breed standards defined by registries specify an "apple-head" or "apple-dome" skull conformation. Chihuahuas occur in virtually an… See more