Dawn, my older female doberman, is only allowed to wear a harness. She had back surgery when she was a one year old. And she can chew a harness off in less than five minutes. She's perfectly behaved when I walk her. In fact she steps in to her harness. But if I forget to take it off when we get home, or I get distracted then thats another $15 down the drain.Don't know how they could chew on a harness......???