Greyhound, by Steve Smith
Basset hound, by Justin Beckley
Husky, by Huskyboy
Border Collie, by Vicki Blackshaw
Bulldog, by Sebastian Bulldog
Yorkie, by Deanna
Chihuahua, by Beadmobile
Great Dane, by Warchild
Effects of domestication (3 of 4)
Today this is propagated through selective breeding, but initially the changes happened without human intention. The phenomenon can be observed in other domesticated mammals as well.