Capturing and chemically immobilizing a bear can be the most traumatic incident of its life, thus, it is extremely important to justify all capture and trapping procedures. Anyone involved in the chemical immobilization of bear or any wildlife should be trained accordingly. During chemical immobilization and capture operations, a wildlife veterinarian should be consulted and part of the team, whether the capture is for research or other purposes.1 The handling of any captured bear should be performed in a careful manner and as expediently as possible to ensure that no trauma, behavioral distress, or unnecessary discomfort can occur.
In the U.S., federal regulations require that research facilities and entities, animal dealers and exhibitors have an attending veterinarian to consult and provide guidance on capture and chemical immobilization procedures and techniques.1 The Food and Drug Administration (FDA) determines what immobilizing drugs can be used on certain species, including bear. The FDA also requires a registration certificate for those using controlled substances; these are obtained through the U.S. Drug Enforcement Agency (DEA). Personnel or field technicians who may be using or even administering controlled drugs must be working under the supervision of a certificate holder, which is often the consulting veterinarian. The certificate holder is also the party responsible for keeping detailed logs of drug use.2 Some states also have veterinary codes in place which must be adhered to by those participating or engaging in the immobilization and capture of wild animals through chemical means.
In most situations, the capture and handling of wild bear imposes stress. This is a normal adaptive response in which the target animal must expend energy to cope with a threat to its welfare. When a threat is extreme or prolonged however, the stress response can have a damaging effect on bear’s health.2 In such cases, energy is used at the expense of other biologic functions. The consequences of capture-related stress have implications for both the health of the target animal and the interpretation of research results. Understanding the physiologic responses to different methods of capture and handling enables for the appropriate selection of capture and immobilization methods, thus minimizing the length and degree of stress imposed on animals.1
Three species of bears live in North America: These are black bears, brown bears (e.g., Grizzlies), and polar bears.
The North American Black Bear (Ursus Americanus) is brown to black in color, and is the most common bear in North America. These range from the State of Florida north, into Canada and north to Alaska. The black bear is omnivorous, with a diet of mostly vegetable matter. Males reach full size at about eight years of age. Females mate and produce cubs at five to seven years of age. The males usually weigh up to 280kg (600 pounds), although they can occasionally weigh much more. Black bears often live up to 25 years in the wild; older bears have been documented however, the majority of bears seldom live longer than 25 years.
There are several subspecies of Brown Bear (Ursus Arctos), which can be found in Alaska, western Canada, and parts of the northwestern United States. Small populations are also known to exist throughout parts of Europe and Asia. Russia is also reported to have a population of brown bear. Brown bear range in color from almost black, brown to very light brown. Size varies greatly depending on geographic location and general food availability. The largest bears exist along the coast of Alaska and Russia, growing to sizes rivaling that of the Polar Bear. Bears of the North American Rocky Mountains (Grizzlies) tend to be smaller.
Polar Bears (Ursus Maritimus) are among the largest bears in the world, with adult males reaching up to 800 kg. (1760 lbs). These bears inhabit the areas in and around the Arctic Circle. In Canada, the largest male bear recorded weighed 654 kg (1439 lbs).2 The average weight of male polar bears in Canada is about 500 kg (1100 lbs). Adult female polar bears are smaller and average around 300 kg (660 lbs).
Given the wide range of weight and physical characteristics of North American bears, obviously there is no one-size-fits-all protocol for their chemical immobilization.3 It is also important to note that no individual drug meets all of the safety requirements and level of effectiveness for all animals. Most drugs will be administered through intramuscular (IM) injection via remote delivery (darts and dart guns).4 An ideal drug or formulation will be in a high enough concentration that the risk for bruising and or muscle tearing during the liquid pressure injection is minimized.2
Some of the drugs used for the chemical immobilization of bear include:
-Most versatile drug for animal immobilization and capture
-Often painful with injection
-Seizure can result when used alone
-Schedule III Drug
-2.5 times more potent than ketamine; wide safety margin
-Schedule III drug
-Ungulates highly sensitive
-Often induces vomiting
-10-20 times more potent than xylazine
-Enhances xylazine effects and improves the quality of immobilization
-Ungulates and carnivores require higher dosages
The BAM formulation (consisting of Butorphanol, Azarperone and Medetomidine) is also suitable for the chemical immobilization of bear. BAM is effective in a wide variety of species and is known for a quick induction; antagonists provide smoother and more rapid recovery than ketamine or telazol combinations.2
For the chemical immobilization of bear, Chemical Immobilization of Wild and Exotic Animals (Nielsen, 1999) recommends the following dosages and formulations:
| Telazol (mg/kg) |
Ketamine (mg/kg) |
Xylazine (mg/kg) |
|
| Black bear | 7 | 5-9> | 2-4.5 |
| Brown Bear (Grizzly) | 7-9 | 11.1> | 11.1 |
| Polar bear | 8-9 | 6.8> | 6.8 |
For the administration of medetomidine+telazol for bear, the drug volume calculations recommended by the Province of Alberta, Canada are as follows: