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Investigators have an obligation to identify and assess the consequences of their research activities on wild animals, populations and the environment. Whenever possible, action should be taken to avoid, alleviate or minimize any adverse effects. Research activities should include the collection of adequate samples to ensure valid research results, yet be balanced to minimize adverse effects. Investigators should always weigh potential gain in knowledge against the negative consequences of disturbance. Although short-term detrimental effects may result from research activities, research can ultimately yield long-term positive effects for the affected population.
Observer-related disturbance can be characterized in at least two ways. First, disturbances may create biases that affect both the gathering and analysis of data, if the actual process of measurement acts to alter the parameter being measured. Second, research activities might effect the status and well-being of the study subjects themselves. Both effects vary along a continuum from those that are overtly obvious to those that are subtle and difficult to detect.
Although they are usually less severe, many of the effects of field investigations are similar in nature to those that result from non-scientific human activities such as tourism and other general recreational pursuits.
The following provides general guidelines for minimizing the impact of research activities in the field:
1. Researchers should only approach study subjects as closely as is required to satisfy the goals of the study without biasing data. Blinds, telescopic lenses, and other remote sensing devices can be used to gather information about an animal or a sensitive area without actually entering it. Where possible, the entrance to blinds should be concealed or camouflaged to further reduce disturbance.
2. Researchers can time visits or activities to avoid the disturbing the animals during their most sensitive periods, such as when they are breeding or tending to young.
3. Because there are interspecific variations in response to research activities, investigators must be able to reasonably predict the level of tolerance and the reactions of their study species to certain field activities by reviewing the pertinent literature and by consulting with others.
4. Because some habituation to investigator disturbance is possible, maintaining consistency in the timing and intensity of visits may help to alleviate some problems.
5. The selection of a study population that is already habituated to human activity may sometimes help to reduce or eliminate the unwanted side effects of scientific research.
Investigators must also take into consideration the response research animals may have to the sounds, the behaviours and the simple presence of humans. In addition, species that are not under study may be disturbed.
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Whether one is collecting study animals for eventual release or for museum preparations, the same humane considerations should apply. These animals should not be exposed to excessive or inappropriate handling, conspecific aggression, predation, temperature extremes, or undue suffering.
Each investigator should observe and pass on to students and co-workers a strict ethic of habitat conservation. Because many essential details of life history may remain unknown until a study is well along, collecting should always be conducted so as to leave the population and habitat as undisturbed as possible.
The permanent removal of large numbers of animals from any wildlife population should be avoided, unless justified for scientific reasons. Similarly, the collection of large numbers of females from any population for destructive sampling should be avoided unless justified for scientific reasons. Systematists should investigate extant collections for suitable specimens before conducting any field work. If the purpose of an experiment is to alter behaviour, reproductive potential or survivability, the interference should be no more than is determined necessary by the investigator to accurately test the hypotheses under question.
Investigators must obtain and comply with all permits required for the capture, handling and collection of those mammals which are of the correct species and in the appropriate jurisdiction. In addition, they must be familiar with the current list of threatened and endangered species and must comply with all rules and regulations pertaining to these and all other categories of mammals.
Investigators should be familiar with traps and trapping techniques and should choose a trap type that is best suited to the species and type of study. Capture techniques should prevent or minimize injury or damage to the animal. Care should be exercised to avoid accidental capture of non-target species. Special consideration should be given to the setting of capture devices in areas that are frequented by pets and children. Trapping and handling equipment should be routinely inspected and maintained in good working order. At the end of each collecting period traps should be properly closed or removed.
Wild animals are sensitive to heat, cold, thirst, energy deprivation and stress, and investigators must make every effort to avoid trap deaths from such factors as temperature extremes, stress, shock, and capture myopathy. Animals should not be left in traps longer than is absolutely necessary, although this will vary with the species, weather, objectives of the study, and trap type. Traps should be shaded or positioned to avoid full exposure to the sun and, where possible, trapping or netting should be avoided in windy, cold and rainy weather. Captured animals can injure themselves trying to escape, even from metal walk-in traps. These injuries reduce the specimen's scientific value and cause needless suffering. Under extenuating circumstances there may be a need to position traps a long distance from the researcher. In these instances the traps should only be set when the weather is moderate and they should be checked as frequently as possible.
Dependent Young: The trapping of wild animals with dependent young should, as a general principle, be avoided. When this is unavoidable, it must be accompanied by a program to either remove or kill the dependants if the parent cannot return. Every effort should be made, in advance of trapping, to locate lairs and nesting areas to minimize the inadvertent capture of these animals.
Bat Trapping: The capture of bats poses special problems which do not apply to most other mammalian species. Mist netting, in which the animals become entangled in a very fine net, is still the most commonly used technique. Because the captured bats will struggle and increase their chances of serious entanglement or injury, these nets should be monitored continuously. In addition, they should be set away from large concentrations of bats, so that an unmanageable number of animals is not captured at a single time. Harp traps are preferable whenever a large number of bats is likely to be caught at a roost or cave entrance because they help to avoid the trauma that is often associated with the use of mist nets. These traps have two parallel frames supporting a series of vertical monofilament lines. For some unknown reason the bat becomes trapped between the vertical lines and is subsequently funnelled into a holding bag.
Any form of trapping around maternity colonies should be avoided. In addition, researchers should avoid excessive or repeated disturbances of roost sites due to the sensitivity of bats.
In some instances, wildlife research may necessitate the judicious collection of whole animal or tissue specimens in the field. This may be done to provide information on species identification, genetics, population structure and dynamics, comparative anatomy and physiology, evolutionary relationships, behaviour, parasites and diseases, economic factors, geographic and microhabitat distributions, and ecology in natural or disturbed habitats. The knowledge that results from these studies may be applicable to other biological sciences and may help to facilitate decisions involving management policies for all species, whether endangered or economically important, for the conservation of habitats, ecosystem analysis, pest and disease control, predator control and domestication of species.
Many specimens removed from the field are deposited in the collections of natural history museums or biological data banks for future studies. Museum collections are curated repositories for whole specimens and their parts, whereas biological banks are collections of histologically or cryobionically preserved organs, tissues (including live cultures), cells (including sperm and ova) or embryos. Both kinds of repositories allow qualified researchers to study their collections. It is strongly recommended that, when appropriate, voucher specimens should be retained at the conclusion of field investigations, so that they will be available for use by future investigators.
Humane methods of kill trapping and shooting are techniques that kill the animal instantaneously while avoiding damage to the body parts that are required for the investigation.
Shooting may be the most effective way to collect many larger mammal species. Researchers planning to use firearms must be experienced in the proper and safe use of firearms and must comply with laws and regulations governing their use. The firearm and ammunition load should be appropriate for the species to be collected. Every effort should be made to avoid wounding animals, not only to minimize suffering, but also to maximize the probability of retrieving rather than losing the specimen. In the event of accidental wounding, the animal must be tracked and recovered.
The use of kill-traps for collecting scientific specimens must be carefully and appropriately justified. If they are to be used, they should be checked at least once daily and positioned so they avoid or minimize the inadvertent capture of non-target species. For example, snap traps, which are usually set for nocturnal animals, should be sprung early in the day in order to avoid the accidental capture of any diurnal species. Methods commonly used for kill-trapping include snap traps (e.g. Victor trap), Museum Specials (snap trap, modified to reduce skull damage), Macabee traps for pocket gophers, Harpoon traps for moles and Conibear traps for medium sized mammals.
The use of steel jawed traps as kill-traps is not considered to be appropriate because these devices hold the animal rather than killing it immediately. If such traps must be used, they must be checked very frequently in order to minimize the animal's suffering. With this live trapping method, it is the investigator's responsibility to safeguard the trapped animal against the effects of heat, cold, thirst, energy deprivation and stress.
See 2.10.2 Euthanasia of Study Animals
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The nature of restraint will depend upon the procedure and the mammal species involved. Restraint techniques can range from confinement in an enclosure, through various types of physical restriction, to chemical immobilization. Any decision to use physical or chemical restraint in a research project should be based upon an understanding of the behavioural and physical characteristics of the species to be restrained, the field conditions under which the procedure will occur, the knowledge and skill of those persons handling the animals, the goals of the investigation, and the availability of appropriate equipment and facilities. Investigators must use the least restraint that is necessary to do the job in a humane and effective manner, with minimal stress to the animal.
Because many species of mammals are capable of inflicting serious injury to themselves or those handling them, some form of restraint will be necessary. The well-being of the animal under study is of paramount importance and it must be emphasized that improper restraint, especially of frightened or stressed animals, can lead to major physiological disturbances, including hypothermia, hyperthermia, stress, shock and capture myopathy. In addition, the capture of some species of animals may alter their behaviour and predispose them to predation . Many species of mammals do not tolerate physical restraint and in some cases there is a great potential for animal or handler injury. Investigators should not allow unsupervised, inexperienced persons to handle any animal species until adequately trained to restrain, manipulate and release the animals properly. The specific handling characteristics of each taxonomic group is beyond the scope of these guidelines. The researcher should consult the current literature and experienced peers before handling an unfamiliar species. The following are general guidelines that must be considered when a researcher physically restrains a wild species:
1. Wild animals should be handled quickly and without sudden movements, utilizing the minimum number of personnel that are required to safely and efficiently perform the task.
2. Darkened chambers and/or blindfolds alleviate stress and subdue animals. They should be used whenever possible. Excessive noise from loud equipment, vehicles, or talking should be minimized. In addition, the handlers should be aware of the negative responses wild animals may have to touching of any kind.
3. Excessive struggling or stress in the restrained animal can lead to hyperthermia, especially during warm or hot conditions. In some cases the time of day will also be an important consideration with handling efforts focused during cooler periods (dawn/dusk).
4. The time of year can be an important consideration when handling and restraining wild mammals. For example, bison and elk tend to be less aggressive and more easily handled in the wintertime. Many animals may be more readily baited into traps and holding areas when the natural conditions are at their poorest.
5. If possible, researchers should avoid capturing and restraining animals which are gravid, tending young or breeding.
6. When restraining an animal by hand, the force applied and technique should be appropriate for the species in question. The use of gloves may reduce the dexterity of the handler.
7. If muzzles, hoods or holding bags are being used as part of the restraint, the investigator must ensure that the animal's breathing or thermoregulatory ability are not compromised.
8. The mesh size and construction of nets must ensure that the animal cannot force its head through the mesh or easily chew through the net material.
9. Many unconditioned animals will fail to recognize chain link or wire as a barrier. Therefore, any corrals or run fences that are constructed of these materials should be draped with burlap or opaque plastic to act as a visual barrier.
10. In some species there is a natural tendency to follow and move as a group. This behaviour can be used to facilitate movement through corrals and run-ways.
11. Movement through solid-sided chutes will be facilitated if the chute is constructed with a curved path and provides a visual escape pathway (i.e. light at the end).
12. When animals are confined in chutes or corrals, stress can be reduced by providing visual barriers which will allow the animals to conceal themselves from handlers and conspecifics.
13. If corrals or chutes are used for confining animals they should be equipped with drop hatches or escape doors to permit the emergency release of animals that become cast or seriously distressed.
14. If body squeezes are used to restrain and handle wild ungulates, they should be adequately constructed and/or padded in order to avoid animal injury.
15. If circumstances increase the potential for human or animal injury, the researchers will terminate the exercise.
Prolonged, distressful restraint should not be performed. Administration of a tranquillizer or sedative to an animal that is physically restrained for longer periods of time may help to prevent injury to both the animal and the handlers. In some circumstances, it is advisable to use general anaesthesia for restraint in the field, particularly for larger or dangerous species. Invasive procedures may require some form of physical restraint initially, but may require subsequent analgesia and/or chemical immobilization (see General Principles of Chemical Restraint Section).
Although some wildlife projects may involve the use of oral or intravenous agents, most field situations utilizing chemical immobilization will require the intramuscular administration of drugs. In some cases these will be given with a hand-held or jab-stick syringe with the animal physically restrained or confined. In other instances the drugs will be given with a projected syringe or dart. Drugs administered by projectiles can seriously wound or kill the target animal if a vital organ, a major blood vessel or a non-target area of the body is penetrated. Therefore, heavily muscled areas must be targeted when darting wild animals.
Researchers should be capable of monitoring the anaesthetized animal and providing the appropriate support measures should an anaesthesia emergency occur. Researchers must take great care in selecting a drug or drug combination for field use. Every anaesthetic agent has specific advantages and disadvantages, and there is no single agent that is suitable for the chemical immobilization of all mammalian species under all circumstances. Safe and effective drug dosages will vary with the species, age, sex and body condition of the animal. In addition, there can be individual and seasonal variations in the response to agents. It should also be realized that drugs used for wildlife immobilization have the potential to seriously affect both animals and humans involved.
It is essential the researcher and all field personnel be familiar with the consequences of drug exposure and be trained to take appropriate action in the event of an accident with animals or humans. The immobilization of wild animals should only be performed by trained personnel who have successfully completed a Ministry Chemical Immobilization Training Course (see Ministry Chemical Immobilization of Wildlife Policy).
There is tremendous taxonomic variation in the response to analgesics, sedatives, tranquillizers and anaesthetics, and dose extrapolation from one species to another should not be routinely attempted. An outline of the numerous drug and drug combinations that have been assessed and recommended for use in wildlife is beyond the scope of these guidelines. Detailed and current information on the recommended immobilization procedures for most North American species are published. Pertinent literature, experienced professionals, and the Ministry of Wildlife Veterinarian should be consulted before a researcher initiates a project involving the immobilization of wildlife species. Where possible, investigators should assess the effects of new immobilization chemicals and procedures on captive individuals before incorporating them into field studies. (See also Chemical Immobilization of Wildlife Manual).
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Most studies require individual animals to be marked for identification. Marking techniques can have a wide variety of effects ranging from short-term discomfort, to long-term influences on breeding and survival. It is essential, for the welfare of the animal and the integrity of the research results, that the marking procedure not adversely affect the normal behaviour, physiology, ecology or survival of individuals. In choosing an acceptable marking technique, the investigator must consider the nature and duration of the restraint that is required for its application, the amount of tissue that is removed or damaged, the amount of momentary or prolonged pain that is involved and the potential risk for infection. In many cases it has been possible to reduce the harmful effects of the mark by careful design, with special consideration to colour, attachment position, mass, and the season in which it is applied. In general, investigators should not assume that marking procedures will have no adverse effects on their study subjects and should make efforts to evaluate any such influences. Where possible, investigators should assess the effects of new marking procedures on captive individuals before incorporating them into field studies. It is desirable for the scientific community to encourage ancillary research that specifically addresses the effects of marks and devices. Preferably, such research, which makes comparisons between marked individuals and controls, can be initiated in association with current studies. Because of the difficulty of providing appropriate controls, there are few systematic studies that assess the potential adverse effects of marking procedures. Many of the cautions mentioned here are based on unpublished observations.
In general, for a marking procedure to be effective, it should meet as many of the following criteria as possible:
1. The animal should experience no immediate or long-term hindrance or irritation from the mark or marking procedure.
2. The animal should suffer no adverse effects on its normal behaviour, physiology, longevity, social life, ecology or survival.
3. The mark should be able to be applied quickly, easily and with minimal pain.
4. The mark should have readily visible and distinguishable digits and/or colours in order to identify individuals or groups as required.
5. The mark should be effective in allowing the researcher to meet the objectives of the study and persist on the animal until research objectives have been fulfilled.
Hot branding has been used in a number of instances to imprint identification numbers on the horns and skin of wild mammals. This method produces third-degree burns which lead to the production of visible scar tissue. Because of the pain associated with this procedure, this method is not commonly recommended.
Freeze branding (cyro-branding) appears to be more acceptable than hot branding for marking wildlife because it is less painful and the possibility of infection is reduced. This technique, which was originally developed for the identification of livestock, has been used with varying results in several wildlife species.
Tattooing is a common method of identification and has been used successfully in many species. Tattoos have been applied to the inside of the lip, the ear, and the thinly-haired area of the groin. The location and proper application of the tattoo will influence its future readability. In most cases, the animal must be recaptured or examined after death in order to read this type of mark.
Techniques that involve the removal or damage of tissue, such as toe, tail, or ear clipping are essentially forms of mutilation. These procedures may have adverse effects on the behaviour and survival of wild animals and their use in marking free ranging wild species cannot generally be condoned. It is strongly recommended that alternative marking techniques be used in field research. However, in those few instances where removal of tissue is not judged to impair the normal activities and survivability of the marked animal and does not cause bone damage, pain or severe blood loss (e.g. ear notchings of small rodents), these marking techniques can be utilized. When toe or tail clipping are felt to be the only methods that can meet the requirements of a particular study, their use should be appropriately reviewed and approved by a review or animal care committee before implementation.
The removal of toes must never be performed on animals that use them for activities such as burrowing (ground squirrels) or climbing (red squirrels), or on animals where important bone structures have to be removed. When toe clipping is used is used as a marking technique, no more than one toe per foot should be removed.
Ear tags are used to mark many different mammalian species and are usually made of plastic, aluminium, or plated steel. These tags are available commercially in a variety of materials, sizes, configurations and colours. Care must be exercised so that a tag of appropriate size is applied. This will help to reduce the potential problems that are associated with heat loss as a result of increased temperature conductance through a metal tag. By tagging both ears the researcher will help to reduce the chances of a lost identity in the event that one tag is torn out. Application of ear tags during fly seasons or using unhygienic techniques may predispose to localized infections. Researchers should understand the ear anatomy to avoid blood vessels and the appropriate application technique before use.
Consideration should be given to the size of the bat and the type of material used in the band in order to minimize the risk of injury. Tattoo needles have been used to mark wing membranes of bats as an alternative to banding, however, these marks were not always visible after five months.
Adjustable and/or expandable neck collars or bands, in a variety of materials with visible colour bands and numbers, are a common method of identifying wild mammals in field studies. These have been used successfully to mark bighorn sheep, deer, elk, moose, bison, and antelope. The size of the collar must be carefully selected in order to allow for normal growth and activity of the study animal.
Modifications to neck bands have been introduced in order to improve their visibility in the field. These alterations include the addition of vinyl coated nylon flags, bells, and battery operated neon lights or light emitting diodes which allow for night observations of species such as deer and beaver. Because these modifications may attract predators and interfere with the normal behaviour and social interactions of the marked animal, their use is justifiably limited.
Tetracycline, a fluorescent marker, has been administered orally or as an injectable as a permanent label of bones and teeth of several species.
The use of radioisotopes as markers in natural systems may be valuable. However the application of these agents should only be undertaken with caution. Researchers are required by law to have special training and to observe certain precautions. In addition, a licence is required which outlines the safety procedures, the disposal of waste material, and the release of isotopes into natural systems. The potential use of these agents must be evaluated with consideration to the possible deleterious effects that these agents may have on the study animal, its predators and the public.
Radioisotopes have been injected into captured mammals prior to their release. This method has allowed researchers to estimate population size by counting radioactive droppings.
A chemoluminescent tag, using Cyalume® injected into hollow glass spheres as a light source, has been cemented to the mid-ventral fur of bats allowing their flight to be tracked at night. The light resulting from this tag lasts from two to three hours and is visible from a distance of 200 m.
Beta lights are another light source useful in tracking small fossorial mammals. They consist of glass capsules coated with phosphor and filled with tritium gas. Beta lights last up to 20 years and can be seen up to 400 m. However, their use must be approved by radiation authorities.
Dyes have been used to colour the hairs in numerous species of mammals, including deer, mountain goats, wolves, ground squirrels, bighorn and Dall sheep, , peccary, and snowshoe hares. Some of the dyes used are Nyanzol A, Nyanzol D, blackpowder, clothing dyes, human hair dyes, red and orange aniline dyes, and picric acid. The method of application of these materials has varied from simply painting the dye on the animal to the use of compressed air sprays or paint balls. They have been administered from the ground, helicopter carried paint ball guns or from aircraft rigged with crop spraying devices. Care must be taken to use non-toxic dyes.
Paint has been used to mark horns of bighorn sheep and bison and has also been sprayed directly on the hide. A commercial paint pistol is available that can propel paint pellets up to 15 m. Coloured plastic adhesive tape has been successfully used as a temporary mark on the horns of bighorn sheep. This material is durable and it is easily applied to immobilized animals. Horns have also been permanently marked with heat branding or the insertion of metal pins.
Coloured ear streamers and ear switches are temporary markers that have been used on larger mammals. The most durable material appears to be vinyl coated nylon. Streamers are usually attached through slits in the ear or by metal tags. The same criticism and limitations to the acceptability of this method exists as for neck bands. In addition, consideration must be given to the behavioural effects of streamers.
Passive integrated transponders or microchips have been used to mark study animals permanently and can be used as an ancillary method of identification. These devices are implanted subcutaneously or intraperitoneally with complications reported rarely. However, animals must be recaptured and special equipment used to identify marked individuals. In addition, the transponders can migrate if applied subcutaneously, and this can make reading them more difficult in larger species.
The attachment of small radio transmitters to free-roaming mammals has become a routine method of monitoring the location and movement of individuals, and has been used successfully in a wide variety of mammalian species. There is little direct evidence that when transmitters are of appropriate size, and are properly attached, they adversely affect research subjects. Transmitters are applied most frequently to the larger species, but with the development of units weighing less than 2 g, they also have applications in the study of smaller species such as bats and rodents.
A wide variety of attachment methods for transmitters are currently in use. The methods for attaching transmitters to a wide variety of taxa are reported in the literature. It is mandatory that investigators who are intending to utilize telemetry in their investigations access those sources which are relevant to their study species. A review of the pertinent literature will help to identify any potentially adverse effects that transmitters may have upon the behaviour, survival and well-being of their study animals. It is strongly recommended that prior to being used in the field, new attachment techniques are reviewed and, if appropriate, evaluated on captive individuals.
Radio transmitters vary in size, longevity and range characteristics, and are available from several commercial outlets. The researcher should choose a transmitter and method of attachment that harmonizes with the anatomy and behaviour of the study animal. Neck collars are the most common method of attachment in mammals, and are most effective in the larger species.
The addition of an external mass to an animal's body can have an adverse effect on its energetics. Therefore, it is recommended that the combined weight of the transmitter and neck collar does not exceed 4 % of the animal's body weight. Special consideration must be given to the attachment of neck collars in those individuals who will undergo significant musculoskeletal growth and in those species that have marked seasonal fluctuations in body condition.
Proper collar width is also critical. If the collar is too narrow excessive undue pressure is applied to the animal's neck resulting in abrasion and pressure necrosis. If too wide, the animal's neck movements may be impeded. Rubber-impregnated nylon webbing (machine belting) and non-impregnated seatbelt type webbing are the materials that are most often used for neck collars. Plastics are often used for smaller species, but their durability and flexibility are affected by temperature and age. The use of collars with protruding or whip antennae should be avoided, particularly on larger, active animals such as moose and bison.
Special attention must be given to the attachment of transmitters in fossorial and arboreal species. Surgically implanted radios have been used on medium sized mammals such as marmots and ground squirrels with similar neck and head width where collars are easily removed. General anaesthesia and veterinary assistance is usually required for the implantation of abdominal transmitters. These devices have a limited range, but if properly installed can be successful. In bats, transmitters have been successfully attached to the fur. As a general rule these transmitters should not exceed 4% of the bat's total weight.
Solar operated ear tag mounted transmitters and subcutaneous transmitters have recently become available for larger mammals in situations where collars are undesirable for esthetic reasons (wildlife viewing).
For more information on this topic consult the RIC (Resources Inventory Committee) manual entitled Standardized Inventory Methodologies for Components of British Columbia's Biodiversity: Wildlife Radio Telemetry.
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It may be necessary to transport animals as part of an experimental protocol or to move them from capture sites to holding facilities. Transport containers and methods of shipping animals will vary widely from species to species. The live traps that are used for capture are usually adequate for transport over short distances. However, if the animals are large or are to be confined for a longer period, these traps may not be suitable. In general, the containers used in transportation must protect the occupants from injury and allow the individual sufficient space so that it can assume a normal posture and engage in comfort and maintenance activities unimpeded by conspecifics. In most cases, animals should be separated. Containers should be padded in those instances where excitable animals or species with delicate bone structures are to be shipped. Adequate ventilation must be provided. For longer journeys, water and food should be provided. The inside of containers should be as dark as possible, while still allowing them good ventilation, to find food or water, and to move about. It is recommended that transport vehicles be equipped so that the transported animals are not exposed to excessive noise, movement or temperature extremes. Proper arrangements should be made to ensure that animals arrive at destinations during normal working hours, rather than on weekends or holidays.
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Wild animals used in captive studies should be as healthy and free of trauma as possible. Some exceptions to this rule include investigations into the effects of environmental stress and disease.
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Only trained, experienced personnel should take tissue or blood samples from live mammals. The use of local or general anaesthetics may be required if the anticipated pain from the procedure is more than mild or momentary.
The estimation of mammal age can be made by examination of antlers, horns or dental eruption and wear, however, for some studies, cementum analysis is required for accuracy. Vestigial teeth such as maxillary premolars are usually extracted. These teeth generally have short roots and can be removed quickly with experience and the appropriate instruments. The removal of permanent incisors in ungulates is extremely painful due to large dental roots and can subsequently impair feeding on a permanent basis. The scientific literature favourably compares the estimation of age by non-invasive techniques and cementum analysis in ungulates, thus removing the necessity of incisor removal. Extraction of these teeth should only be done if justified by review, by experienced personnel and with full analgesia under general or local anaesthesia.
The most common method for the collection of blood from mammals is venipuncture. Many sites are accessible but preferred veins vary with species (for example, femoral vein in bears, cephalic or jugular in cervids). Blood may be withdrawn by needle and syringe and decanted into blood tubes or removed directly into blood tubes using double ended needles. Training and experience in venipuncture can ensure a rapid and painless procedure.
In general, it is advised that no more than 10 - 20 % of the animal's blood volume (approximately 1.5 - 2.5 % of lean body mass) be collected during sampling. Following blood sampling, hemostasis can usually be achieved by applying direct digital pressure to the collection site for several minutes. The bleeding should stop before the animal is released.
In addition to blood, study protocols may require the collection or biopsy of other tissues such as fat, muscle, liver, and skin. Before initiating a project involving invasive biopsy techniques, the researcher should conduct an adequate peer and literature review. Investigators should only collect the minimum amount of tissue that is necessary to reliably satisfy the research goals. In some instances, analgesia or anaesthesia may be required to effectively and humanely obtain the necessary sample. The survival of animals that are released following a biopsy procedure should not be compromised. It should be noted that non-invasive sampling is the preferred alternative.
Diet information may be gathered as part of ecological and nutritional studies. The sacrifice of animals for stomach contents is rarely justified. Instead, it is preferable to collect prey remains or fecal material for analysis.
Injections of appropriate solutions or implants, whether subcutaneous, intramuscular, intraperitoneal or intravascular, may usually be made with very little effect on survival or normal animal behaviour. The personnel performing these procedures should be properly trained. Some solutions may be irritating or dangerous to the subject if they are not properly injected. Implants may require major surgery under general anaesthesia and may migrate or become inactive if they are not properly inserted.
Before being used in the field, it is strongly recommended that new techniques are evaluated on captive individuals. A review of the pertinent literature will help to identify any potential adverse effects that injections or implants may have upon the behaviour, survival and well-being of the study animals.
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When performing major manipulative procedures, humane principles should always be the first priority. There is no justification for accepting substandard care of study animals due to a lack of knowledge or expertise.
The conditions governing the adoption of procedures may depend upon the intended fate of the subject. In general, four categories of subjects can be distinguished:
1. Wild animals in the field that are to be released immediately upon recovery.
2. Wild animals brought into a holding facility that will be released after recovery.
3. Wild or captive bred animals that are to remain captive permanently or for an indefinitely long period after the procedure.
4. Animals that will be euthanized without recovery.
For any animal that is to be released to the wild, the prime consideration should be that the procedure will have a minimal effect on the animal's subsequent survival and reproductive potential. No animal should be released back to the wild until it is deemed to be sufficiently recovered to perform normal behaviours, including predator evasion and feeding. If the purpose of the experiment is to alter survivability or reproductive potential, then the interference should be no more than is necessary, as judged by the investigator, to test the issue in question. Even animals that are to be held as permanent captives or ultimately euthanized should not be subjected to pain or suffering.
The acceptability and practicality of a procedure will vary with the experience and skill of the investigator. Procedures should only be performed after consultation with and preferably under the guidance of an experienced wildlife veterinarian. For any invasive procedure that is more complicated than a simple injection there should be supervised practice on a model or a carcass before it is attempted on a living subject. The ultimate goal of practice is to be able to perform the technique quickly and efficiently with minimal tissue trauma.
A major portion of surgical trauma for many wild animals is the physical or chemical restraint that is associated with the procedure. Anaesthesia can be physiologically stressful and many animals are severely stressed by prolonged handling. Therefore, a technique will be more successful if it can be performed rapidly, but not hastily. Invasive procedures, if performed correctly, need not affect the survival or reproductive potential of the subject.
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Whenever it is practical, researchers should release field trapped animals following the completion of their studies. However, there are exceptions to this and, as a general rule, field trapped animals should be released only:
1. At the site of the original capture (unless conservation efforts dictate otherwise).
2. Where it can be reasonably expected that the released animals will re-establish their former social status.
3. When the weather conditions and the season are conducive to survival.
4. If it is in the best interest of the study subjects, and if their ability to survive in nature has not been impaired.
5. When the released animals are not a health hazard or are otherwise detrimental to the existing populations in a specific geographic area (for example, when they do not jeopardise the genetic integrity of a population or carry a potentially infectious disease).
6. When the animals' release is compliant with federal, provincial or local laws.
Captive animals that cannot be released should, whenever possible, be distributed to colleagues for further study. However, if the animal is in chronic distress or pain, or if release or rehabilitation is neither feasible nor likely to succeed, then euthanasia may be the only alternative. If animals must be destroyed subsequent to a study, then it should be done using a method of euthanasia which is humane, instantaneous and considered acceptable (see Reference section). In addition, the method of euthanasia should not interfere with any future research potential of the carcass or any specific post mortem analyses. In both the field and the laboratory, the investigator must be careful to ensure that euthanized animals are dead before disposal. Disposal of carcasses must be in accordance with acceptable practices as required by municipal or institutional regulations. Animals containing toxic substances or drugs should not be disposed of in areas where they may be scavenged or become part of the natural food chain.
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