Because of the manner in which fish "bite" it is quite possible for a fish to remove bait from a hook without actually taking the hook into its mouth far enough for the hook to engage the fish. Fish do not bite like other animals. When a fish bites, it sucks water in through its mouth and expels the water through its gills. This sucking action is the manner in which fish take food into their bodies. Since the bait is generally buoyant in water, the fish can approach the hook and suck bait away from it without taking the hook itself, causing many a lost catch.
Various devices have been made in an effort to prevent fish from removing the bait without taking the hook, but such devices have generally been found unsatisfactory because, first, they are generally made of metal thereby adding extra weight to the hook which can be felt by the fish, causing the fish to respond to the extra weight in the mouth by expelling it; secondly, the previous devices are cumbersome and take up extra space on the fishing hook and, third, they require extra effort to apply, reducing the likelihood that a fisherman will use the device. Finally, such devices frequently can be seen by the fish, causing them to avoid biting the bait. Any such devices which have been previously developed are for live bait only.
Such devices generally are made of a piece of metal mounted on or connected to the fishing hook, or a metal bail encircling the bait, or a hook with opposing gripping metal jaws or hook portions.