ABSTRACT
Rhesus monkeys are used in biomedical studies because of their close phylogenetic relationship, physiological and immunological similarities to humans. They have been the most commonly used species of monkeys in biomedical research for decades (Capitanio et al. 2006). Consequently, more is probably known about the biology of this species than any other nonhuman primate. The results of investigations with them, however, can be modied due to varying psychological and physical stresses that are imposed upon these subjects in association with the studies. Immobilization of the monkey to obtain blood samples for hematologic assessments is a particular concern (Coleman et al. 2008). Erythrogramic values are subject to aberration during stress (the alarm reaction), and immediately reect the current anxiety that is perceived by the subject. In many if not most circumstances, the actions and appearance of the monkey under scrutiny do not reveal the degree of stress that is present. Thus, the investigator is often unaware whether the derived data indicate an unstressed normal physiologic status or an altered condition. Some hormones normally present in the circulation have been identied as sensitive to stress (e.g., cortisol, testosterone, growth hormone, and prolactin).
