The idea for knotting a rolled sheet of rawhide is over 30 years old. Originally it was used as an entertainment toy or as a tool for redirecting the instinctive chewing urge of a dog. There is still no other product tough enough to withstand vigorous canine chewing, soft enough not to damage teeth and yet be highly digestible. With the advent of modern soft food diets, chews have played a greater role in ensuring that dogs get effective teeth cleaning and gum conditioning.