Whether or not a wild animal needs to be chemically immobilized is generally a function of accessibility to the animal, the potential risks to the animal and its handlers associated with handling it, and the degree of invasiveness of the procedures involved. Circumstances necessitating the need for the chemical immobilization of wild animals can include, but are not limited to:
- Relocation
- Conservation efforts
- Medical treatment
- Breeding programs
- Escaped containment in a zoo setting
- Scientific research
If there is a high probability that an animal will injure itself or its handlers during a procedure, it should be chemically immobilized. In many cases, this is carried out by remote delivery of a dart containing immobilizing drugs. Tranquilizing an animal through the use of these darts is a highly-specialized procedure that provides the most effective means to capture very mobile, unapproachable, large and/or dangerous animals. In most cases, captured animals must be sedated to allow safe handling and transportation and to reduce the detrimental effects of stress during capture and restraint, so the remote delivery of tranquilizing drugs is highly beneficial for the welfare of the animal.1
Types of Darting Devices and Systems
Today, there many brands of commercially-available darting equipment on the market, DanInject®, Pneu-Dart®, TeleDart® and Cap-Chur™ being among the most popular of these. Types of dart delivery systems can be classified as falling into one of three groups based on the method used to project the dart.
Manual dart systems are limited to blowpipes and pole syringes. Blowpipes require considerable practice and user skill, but they are inexpensive and have an effective range of 10–15 meters.1
Pressurized gas systems use carbon dioxide to deploy the dart. These are often used by capture teams and zoos, and have an effective working range of up to 75 meters. Operating pressure can be set low enough to project darts with minimum necessary impact to result in drug delivery over distances from just 3 meters but can be increased to achieve longer ranges. Pressurized systems are available as pistols or rifles that have interchangeable barrels allowing a variety of different dart sizes to be used.
Powder-charged systems are similar to pressurized systems except that they typically use a blank charge to propel the dart. Various charges are used for different distances. Powder-charged systems have the longest range, from 40–100 meters depending on the system. This type of system would be the most likely to be used in the field, approaching an animal on foot, or in a ground-based vehicle or helicopter.
Interested in learning more about safe capture? The San Diego Zoo now offers courses in safe capture techniques and best practices. Learn reliable, safe, and effective techniques for the species you work with and the scenarios you encounter!
1Arnemo, Jon & Kreeger, Terry. (2018). Handbook of Wildlife Chemical Immobilization 5th Ed. Sunquest Publishing, 2007, 432 pages.
