Although the effects of the environment may not be readily noticeable to the investigator, variations may occur, resulting in research variability and potentially erroneous conclusions ( Roe 1965 Magee 1970 van der Touw et al. Even subtle changes in the living and experimental environment can lead to confounding and variable research outcomes. Whether living in a tightly controlled internal environment or an outdoor environment subject to weather changes, animals, through their physiological and behavioral processes, will respond to various stressors in their environment ( Hale 1969 Sossinka 1982 Price 1984).
Animals used in research, teaching, and testing are complex living creatures that respond to environmental parameters.
