Trying to find a harnes for my pet squirrel. He is 7 months old. I think that his neck is a little more than 1 1/2" but not quite 2". I bought one that it said that it was for ferrets, pet rats, and young guinea pigs the size small is 5" - 7.5" body and 4" - 6" neck but he still got out of it. Can you tell me if the red one you have for ferrets will be ok? It does not give measurements. Thank you I would appreciate it.