Some archaeologists believe dogs were the first tamed animal, accompanying humans 30,000 years ago.
Dogs evolved from their wolf ancestors slowly, then quickly, as breeding improved.
Dogs as little as a dollar bill and as heavy as an apple exist nowadays.
In the next slides, Stacker examined American Kennel Club data on 193 dog breeds, from Afghan hounds to Yorkshire terriers.
The following list ranks the 96 largest dog breeds by size index, which includes their average maximum height and weight.
Discover the personalities and histories of some of the world's largest dogs.
There are also huge dogs that hunt, defend, and rescue drowning fishermen.