Returning to the original question of the thread - if you want to control any animal, you do it by attaching something to the most sensitive part of the animal that you can reasonably get at - think also about a bull being led by a ring through its sensitive nose, or a horse with a steel bit in it's mouth. Putting a collar round a dog's neck is the obvious place to put something to control it - it's likely to stay there, not come off. Slaves were also collared. I don't like to control my dog by the neck. She wears a collar for ID purposes, but her lead is attached to a comfy fleece-lined harness.