Animal Capture
Animal capture (or wildlife capture) is an event in which an animal is caught and restrained to varying degrees by humans. Reasons for wildlife captures vary widely: marking, collaring with tracking devices, disease surveillance, translocations related to conservation, commercial or nuisance, treating injuries and taking samples for research are just a few examples. Information about movement patterns and numbers of animals is often required for population management.1
Increased interest has led to the widening study of disease monitoring and understanding the complex relationship between wildlife, people, domestic animals and the environment. Conservation and management of natural animal populations requires knowledge of their dynamics and associated environmental and management influences.1 Informed management requires periodic estimates of the population of specific species and models for projecting consequences of management actions for subsequent state dynamics.
Physical vs. Chemical Restraint
Wildlife capture can be a complex proposition that should be carefully planned. With regard to animal capture techniques, there are generally two types: physical capture and chemical immobilization. Physical capture describes the use of devices such as traps, nets and snares which restrict an animal such that it can be handled or chemically immobilized. Chemical immobilization involves the direct use of sedatives and/or anesthetic drugs to facilitate capture.
Many non-chemical methods for capturing wildlife are commonly used. These include traps, net-guns, drop-nets, drive nets or corral traps.1 Foothold traps and foot snares are sometimes used for species that are difficult to approach. Because of the cruelty inherent in the use of steel-jaw traps however, they've been banned in many countries, and in several U.S. states.2 When using foothold traps, foot snares or cage traps are used, it is essential to check the traps regularly and often, since animals can break their teeth or claws or incur injuries when attempting to escape.3
Cage traps are also used for smaller wildlife species and many carnivores, with carcasses or pieces of meat are being used to lure the animal inside. Smaller traps may open on one or both ends and have one or more compartments for multiple animals. The animal enters the cage and steps on a treadle, which causes the door to close behind it.1
Chemical immobilization is usually done by remote delivery, using a dart that injects immobilizing drugs into the animal. A wide variety of drugs and drug combinations are used for wildlife captures; these vary depending on factors such as species, sex, venue, conditions and requirements. When discussing wildlife captures, two essential terms are usually involved: sedation and anesthesia. In the former, the immobilized animal is incapable of movement, or its movement is restricted by immobilizing drugs. General anesthesia is a drug-induced state characterized by suppressed reflexes and loss of consciousness of the animal.1
Risk Factors
There are multiple capture-related challenges and risks for both animals and humans involved. In the field, events such as sudden weather changes, injuries, failure of equipment, drug complications or accidental exposures, unexpected physiological reactions or surgical complications can arise. Proper planning is essential, and can often prevent or mitigate these risks, since prevention is typically easier that dealing with an accident or medical condition that has already occurred.
Stress is the biological reaction to any adverse stimulus, internal or external, that tend to disturb an animal’s internal homeostasis.1 Stress alters an animal’s normal physiology and can induce pathological states. In this context, stress is usually caused by excessive exertion or fear during capture. The many unfamiliar events that occur during these procedures can lead to both psychological stress as well as the physical stress of muscular exertion.1,2 These can lead to conditions such as capture myopathy, a stress-induced syndrome frequently encountered in captured wild animals.
Additionally, field conditions in wild animal captures are often unpredictable and an animal can hurt itself while escaping in difficult terrain. Misplaced darts can cause fractures and muscle injuries or damage lungs and cause pneumothorax.4
Training in Animal Capture
Today, there are many organizations which offer education in animal care and handling, and many of these cover aspects of animal capture. Animal handling requires skill, competence, knowledge of risks and diseases, and respect for the humane treatment of the animals being handled. It is important to know the proper safety precautions relative to animals being handled, to have a clear understanding of relevant laws, and to have a plan for the final disposition of animals in a variety of circumstances.
Organizations such as the Global Wildlife Resource (GWR) offer animal care and handling courses focused on wildlife. Certification and non-certification courses in animal care and handling can provide a good foundation for those interested in this area of study. In most localities, such organizations provide at least some training geared toward various certifications in keeping with federal, state and local regulations pertaining to animal handling.
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!
1Animal Care and Use Committee (1998) Guidelines for the Capture, Handling, and Care of Mammals as Approved by the American Society of Mammalogists. In: J. Mammology 79:1416-1431.
2Hubert, W., et. al. Passive Capture Techniques (2012). Nebraska Cooperative Fish & Wildlife Research Unit, Staff Publications, 111.
3Cattet M.R., et. al. Physiologic responses of grizzly bears to different methods of capture. J Wildl Dis. 2003 Jul;39(3):649-54. doi: 10.7589/0090-3558-39.3.649. PMID: 14567227.
4Arnemo, Jon & Kreeger, Terry. (2018). Handbook of Wildlife Chemical Immobilization 5th Ed. Sunquest Publishing, 2007, 432 pages.
About NexGen Pharmaceuticals
NexGen Pharmaceuticals is an industry-leading veterinary compounding pharmacy, offering sterile and non-sterile compounding services nationwide. Unlike other veterinary compounding pharmacies, NexGen focuses on drugs that are difficult to find or are no longer available due to manufacturer discontinuance or have yet to be offered commercially for veterinary applications, but which still serve a critical need for our customers. We also specialize in wildlife pharmaceuticals, including sedatives and their antagonists, offering many unique options to serve a wide array of zoo animal and wildlife immobilization and anesthesia requirements.
Our pharmacists are also encouraged to develop strong working relationships with our veterinarians in order to better care for veterinary patients. Such relationships foster an ever-increasing knowledge base upon which pharmacists and veterinarians can draw, making both significantly more effective in their professional roles.
Disclaimer
The information contained in this blog post is general in nature and is intended for use as an informational aid. It does not cover all possible uses, actions, precautions, side effects, or interactions of the medications shown, nor is the information intended as medical advice or diagnosis for individual health problems or for making an evaluation as to the risks and benefits of using a particular medication. You should consult your veterinarian about diagnosis and treatment of any health problems. Information and statements have not been evaluated by the Food and Drug Administration ("FDA"), nor has the FDA approved the medications to diagnose, cure or prevent disease. Medications compounded by NexGen Pharmaceuticals are prepared at the direction of a veterinarian. NexGen Pharmaceuticals compounded veterinary preparations are not intended for use in food and food-producing animals.
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