Capturing and restraining an injured or ill animal is extremely stressful, and the rehabilitator’s primary goal is to reduce stress by minimizing pain and distress.

Stress is the body’s reaction to abnormal states (e.g. infection, extreme temperature, injury, fear) that disturb the normal physiological equilibrium. Fear, fright or rage activates the hypothalamus, causing massive discharge of the sympathetic nervous system to prepare the body for vigorous muscle activity.
University of Alaska Fairbanks

Stress can result in capture myopathy, a disease complex associated with capture or handling of any wild species. Capture myopathy occurs when an animal cannot cool itself; the key feature of capture myopathy is hyperthermia (an increase in body temperature).

Factors involved in capture myopathy include:

• Drugs used for restraint (particularly xylazine) cause an increase in body temperature. For this reason, these drugs must be reversed after use.
• Muscle Pump: muscles exert a pumping action as an animal moves and this aids blood flow. When normal movement is taking place 15% of the total blood volume is in the muscles. In a drugged animal, 25% will pool in the muscles causing a drop in blood pressure. Lactic acid builds up and cooling is reduced.
• Fear: the single most important factor in capture myopathy.
• Environmental temperature

There are four categories of capture myopathy: peracute, acute, subacute and chronic.

Peracute capture myopathy: death may occur in a matter of minutes due to low blood pH, acidosis, potassium release from damaged muscles and heart failure. There are few post-mortem signs.

Acute capture myopathy: the animal lingers before it dies. Muscle rupture may occur and the animal, if able to stand, will be ataxic. The condition could be confused with enzootic ataxia. Death occurs in 24 - 48 hrs.

Sub-acute capture myopathy: acidosis causes muscle and kidney damage. Urine may be a dark brown colour. Recumbent animals often have their necks twisted back. Death follows within a few days.

Chronic capture myopathy: animals may survive several days or months but will often die suddenly from a heart attack.

Treatment: prevention is the only treatment for this condition. Once the condition starts it is always fatal.
Capture Myopathy

An animal that is injured, ill or orphaned is already experiencing great stress. It may be in pain, dehydrated, starving and fearful.

To minimize further stress as much as possible, the rehabilitator must be prepared and have a plan of action, as well as all the necessary equipment. For this reason, it is crucial that new wildlife rehabilitators or volunteers who will be involved in rescues undergo training to learn proper techniques of capture, restraint, handling and transport.

Training seminars in capture, restraint, and chemical restraint are available from

If there are no seminars offered in your area, contact your local wildlife agency (e.g. Department of Natural Resources). Resource officers are well trained in capture and restraint, and may be willing to share information and techniques.