Appropriate permits must be obtained for the live capture and subsequent use of animals in 
captivity. Typically, wild-caught animals have internal and external parasites. Quarantine of 
newly arrived animals is needed to protect the health of those already in the colony, to 
determine the health status of the incoming animals, and to safeguard the health of 
personnel. The quarantine also allows the animal's metabolism to adjust to the new 
environmental conditions and gives the animal time to recover physiologically, 
immunologically, and behaviorally from the stress of capture and transplantation. 
An important concern for those working with wild-caught animals is the final disposition of 
the animal after experiments are completed. At least three options may be relevant, including 
euthanasia, placement in another research facility, or the return of the animals to their natural 
habitat. Resolution of this issue depends on a number of practical as well as ethical concerns. 
If the animal is to be returned to its native environment, the following should be considered: 
(1) the likelihood of the animal’s readjusting to nature, with time in captivity as one relevant 
marker; (2) the specific environment to which it may be returned (i.e., the same or similar?); 
and (3) the possible impact on that environment. Because all three options have costs and 
benefits depending on the species and the circumstances, it may be necessary to determine the 
fate of wild-caught animals on a study-by-study basis. These issues should be addressed 
during the permit application process. Information on social manipulation can be found in 
Chapter 8, Social Variables (see also Novak et al., 1998). 
Research on infanticide examines the response of adults to young offspring to make 
inferences about social organization and patterns of parental care. This research often entails 
injury or death to neonates and thus is problematic because of the high probability of pain 
and distress. Offspring can be placed in a protective barrier (e.g., mesh cage) to reduce the 
potential for injury from adults. Aggression toward offspring in mesh cages is then used in 
place of actual killing of offspring. In some species, however, this procedure inhibits the 
infanticide response. Extensive observation can reduce the probability of injury. Adults are 
observed closely for behavioral signs of imminent attack (e.g., lunges in rodents). When these 
signs are observed, the adult is then distracted or removed from the testing environment 
before killing occurs. 
Studies of predator/prey relationships can provide clues to the animal’s ecological niche, 
cognitive capacity, sensory capacity, and adaptations as a predator or as prey. Such work also 
provides insights into the neural mechanisms of aggression when coupled with standard 
neurophysiological and neuropharmacological procedures. A major welfare issue is the 
occurrence of pain and injury. The prey species is usually the one at risk for injur}'. It is 
sometimes possible to protect prey from physical attack with the use of holding cages. 
However, this procedure is useful only if predators continue to make predator}’ moves under 
such conditions. Modeling aspects of the predation sequence can sometimes eliminate risk ot 
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