A whip is a tool or weapon designed to strike humans or animals to exert control through pain compliance or fear of pain. They can also be used without inflicting pain, for audiovisual cues, such as in equestrianism. They are generally either a firm stick designed for direct contact, or a flexible line requiring a specialized swing. The former is easier and more precise, the latter offers longer reach and greater force. A hunting whip combines a firm stick (the stock or handle) with a flexible line (the lash or thong).
Whips such as the "cat o' nine tails" and knout are specifically developed for flagellation as a means of inflicting corporal punishment or torture on human targets. Certain religious practices and BDSM activities involve the self-use of whips or the use of whips between consenting partners. Misuse on animals may be considered animal cruelty, and misuse on humans may be viewed as assault.
Use
Whips are generally used on animals to provide directional guidance or to encourage movement. Some whips are designed to control animals by imparting discomfort by tapping or pain by a full-force strike that produces pain compliance. Some whips provide guidance by the use of sound, such as cracking of a bullwhip. Other uses of whips are to provide a visual directional cue by extending the reach and visibility of the human arm.
In modern times, the pain stimulus is still used in some animal training, and is permitted in many fields, including most equestrianism disciplines, some of which mandate carrying a whip. The whip can be a vital tool to back up riding aids when applied correctly, particularly when initial commands are ignored. However, many competition governing bodies limit the use of whips, and severe penalties may be in place for over-use of the whip, including disqualification and fines. Improper overuse of whips may be considered animal cruelty in some jurisdictions.
Whip use by sound never or rarely strikes the animal; instead, a long, flexible whip is cracked to produce a very sharp, loud sound. This usage also functions as a form of operant conditioning: most animals will flinch away from the sound instinctively, making it effective for driving sled dogs, livestock and teams of harnessed animals like oxen and mules. The sound is loud enough to affect multiple animals at once, making whip-cracking more efficient under some circumstances. This technique can be used as part of an escalation response, with sound being used first prior to a pain stimulus being applied, again as part of operant conditioning.
Whips used without painful stimulus, as an extension of the human hand or arm, are a visual command, or to tap an animal, or to exert pressure. Such use may be related to operant conditioning where the subject is conditioned to associate the whip with irritation, discomfort or pain, but in other cases, a whip can be used as a simple tool to provide a cue connected to positive reinforcement for compliant behavior. In the light of modern attitudes towards the potential for cruelty in whips, other names have gained currency among practitioners such as whips called a "wand" or a "stick," calling the lash a "string" or a "popper".
Cracking
The loud sound of a whip-crack is produced by a ripple in the material of whip travelling towards the tip, rapidly escalating in speed until it breaches the speed of sound, more than 30 times the speed of the initial movement in the handle. The crack is thus a small sonic boom. Whips were the first man-made objects to break the sound barrier.
Most stick type whips cannot make a crack by themselves, unless they either have a very long lash, such as a longe whip, or are very flexible with a moderately long lash, like certain styles of buggy whip. But any design can be banged against another object, such as leather boot, to make a loud noise. Short, stiff crops often have a wide leather "popper" at the end which makes a particularly loud noise when slapped against an animal, boot, or other object.
Types
Stockwhip
Stockwhips (or stock whips), including bullwhips and the Australian stockwhip, are a type of single-tailed leather whip with a very long lash but a short handle. Stockwhips are primarily used to make a loud cracking sound via special techniques that break the sound barrier, to move livestock (cattle, sheep, horses, etc.) away from the sound. It is generally not used to actually strike an animal, as it would inflict excessive pain and is difficult to apply with precision.