Tranquilliser gun

A tranquilliser gun, also called a capture gun or dart gun, is a non-lethal gun which shoots tranquilliser darts filled with tranquilliser that, when injected, make the target animal sleep. Tranquilliser guns have a long history of being used to capture wildlife without injury. Tranquilliser darts can also be fired by crossbow or breath-powered blowgun.

The dart is propelled from the gun by means of compressed gas. On impact with the animal, the inertial momentum of a ball bearing at the rear of the dart injects the dose of barbiturate or other drug into the animal, causing torpor and prostration within minutes. 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.

The tranquilliser gun was invented in the 1950s by New Zealander Colin Murdoch. [http://www.nzedge.co.nz/heroes/murdoch.html NZ Edge Heroes biography of Colin Murdoch] ] While working with colleagues who were studying introduced wild goat and deer populations in New Zealand, Murdoch had the idea that the animals would be much easier to catch, examine and release if a dose of tranquilliser could be administered by projection from afar. Murdoch went on to develop a range of rifles, darts and pistols which have had an enormous impact on the treatment and study of animals around the world.

At the time Murdoch started testing his gun the only tranquilliser drugs available were curare, and alkaloids of nicotine, both of which tended to have fatal reactions in a high percentage of animals shot. In partnership with pharmaceutical companies, he helped develop more sophisticated drugs with precise and safe reactions.

In Kenya in the early 1960s, a team headed by Dr. Tony Pooley and Dr. Toni Harthoorn discovered that different species, despite being of roughly equal size (for example, the rhinoceros and the buffalo) needed very different doses and spectra of drugs to safely immobilise them. In some species the margin of error is very small indeed.

Tranquilliser darts are not included in military or police less-than-lethal arsenals because no drug is yet known that would be quickly and reliably effective on humans without the risks of side effects or an overdose.

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