Engineering:Tranquillizer gun

Short description: Non-lethal gun used to paralyze animals

A Dan Inject Model JM air rifle with a tranquillizer dart

thumb|Baby deer that has been given conscious sedation by dart to induce friendliness and trust

A tranquillizer gun (also spelled tranquilizer, tranquilliser or tranquiliser), capture gun or dart gun, is a non-lethal air gun used to reduce irritability or agitation in animals via anesthetic drugs commonly referred to as tranquilizers. The gun shoots a dart tipped with a hypodermic needle and filled with a dose of tranquilizer solution that is either sedative, comatosing or paralytic. The gun makes it possible for wild animals to be sedated, while domestic animals are sedated in the same manner that humans are.

"Dart gun" can also mean a gun firing a dart which contains a vaccine or antibiotic.

History

The modern tranquillizer gun was invented in the 1950s by New Zealander Colin Murdoch. While working with colleagues to study populations of deer and wild goats introduced to New Zealand, he considered that the animals would be easier to catch, examine, and release if a dose of tranquillizer could be administered by projection from afar. To that end, Murdoch went on to develop a range of rifles, darts, and pistols.

The first modern remote drug-delivery system was invented by scientists at the University of Georgia in the 1950s, and was the direct predecessor to the Cap-Chur equipment used worldwide for decades.

In the early 1960s, a team in Kenya headed by Drs. Tony Pooley and Toni Harthoorn discovered that various species, despite being of roughly equal size (for example, the rhinoceros and the buffalo), needed very different doses and spectra of drugs to safely immobilize them.

Since 1967, hollow bullets with tranquillizers for immobilization of wild animals began to be used in the USSR. In the first half of the 1970s, experimental 9×53mmR cartridges for immobilization of wild animals for 9mm "Los" bolt-action carbine and "flying dart" for 16 gauge shotguns were made and tested. In the mid-1970s, "flying dart" for 12 gauge shotguns and experimental cartridges for immobilization of wild animals for the SPSh-44 pistol were made and tested. In the second half of the 1980s, the standard tranquillizer gun in the USSR was a single-shot IZh-18M shotgun (a dart with a dose of tranquillizer was fired with a blank cartridge).

Characteristics

The dart, usually .50 caliber (12.7 mm), is a ballistic syringe loaded with an immobilizing agent and tipped with a hypodermic needle. The dart is propelled from the gun by compressed gas, and it is stabilized in flight by a tailpiece consisting of a tuft of fibrous material. The needle may be plain or collared, with a barb-like ring to improve retention of the needle and syringe for recovery from the target and to assure that the full dose is administered.

Methods of driving injection upon impact include: gas compression, spring compression, explosive charge, or gas evolution reaction. In one example, compressed air or butane in the rear of the dart pressurizes the tranquillizer solution, while the needle is capped to hold the fluid in place. Upon striking the target, the cap is pierced by the needle as it punctures the animal's skin. With the pressure released, the compressed gas pushes the solution out of the syringe and into the target (see diagrams from Veterinary Technician).

Because of the power of the drugs, the handlers then have to move quickly to secure the animal for transport, monitor its vital signs, protect its eyes and ears, and then inject antidotes when needed. Many large animals are acutely sensitive to stress and can easily die without careful treatment; in order to counter stress in targeted animals, the gun is quiet, and there is usually a valve on the gun to control the dart velocity by varying the amount of gas pressure used to propel it.

Agents

Several immobilizing drugs have been devised for use in tranquillizer darts. These include:

• Azaperone
• Combelen (Bayer)
• Domosedan (Farmos)
• Dormicum (midazolam) (Roche)
• Detomidine (Farmos)
• Fentanyl and Carfentanyl (Janssen Pharmaceutica)
• Etorphine hydrochloride (M–99, Novartis)
• Haloperidol (Kyron Laboratory)
• Immobilon, a mixture of etorphine and a phenothiazine tranquillizer such as acepromazine or methotrimeprazine.
• Ketamine
• Valium (diazepam) (Roche)
• Xylazine (Rompun, Bayer)
• Sodium Thiopental (Abbott)

Military and police use

Tranquilizer darts are not generally included in military and police less-than-lethal arsenals because a human can easily be wrestled to the ground, the pain induced by the dart may cause a suspect to panic and run until they are far away resulting in the officer having to track down the unconscious suspect, language barriers between humans can be overcome (it is generally accepted that while many species of animals do have language, their languages cannot be understood by a human and vice versa), a human can have a deadly allergic reaction to a tranquilizer, and because effective use requires an estimate of the target's weight —- too little tranquilizer will have no effect, and too much tranquilizer will result in death, which can lead to being convicted of second-degree unintentional murder if the target is a human. "If you shot somebody that was small, it could kill them. If you shot somebody who was big or had drugs in their system, it might not do anything." says Newett, of the Justice Department. They are not shot from police helicopters since it is difficult to shoot accurately from a helicopter, a dart will not penetrate a car windshield, car body, car window, car top, or body armor and because dart guns have a limited range and a very slow rate of fire.

Military soldiers can capture a group of enemies by rendering them helpless with tasers, making tranquilizer darts unnecessary.

Further reading

• Harthoorn, Antonie Marinus (1970). The Flying Syringe. Bles. 
• Harthoorn, Antonie Marinus (1976). The Chemical Capture of Animals. Baillière Tindall. ISBN 0702005584. 
• Anti-personnel dart design - patent details
• Blow gun inoculating dart design - patent details