A Russian study tried to breed silver foxes for domesticated traits without a large about of human contact or training. They selectively breed the animals by selecting to breed only those foxes that showed low levels of fear. The actions of the animals over 50 years of breeding is overwhelming. The foxes have developed shorter or curly tails, changes in coat color, head shape, and floppy ears. They also show behaviors like whining at humans and licking and sniffing their hands. Check out the videos, they really are acting like puppies.