Longblades, yes, the Australian Cattle Dog was called a Heeler because they were bred to heel cattle, and they are quite good at heeling people if you don't stop them.
Roo, at 8 months is biting and mouthing hands every chance he gets, he's the wildest pup we've had. You really need ways of distracting them when they are babies, soft toys, empty water bottles, balls etc.. Keep your hands out of harm's way.