Acclimation of Animals


This guideline describes industry standards for acclimation for laboratory animals.

The Guide for the Care and Use of Laboratory Animals (the Guide, NRC 2011) states: "newly received animals should be given a period for physiologic, behavioral, and nutritional acclimation before their use." (p. 111) The length of time for this acclimation period will depend on multiple factors. External factors will affect the stabilization period, for example, the duration/distance the animal traveled to reach the facility and the weather/travel conditions. The species is an important consideration, as smaller animals with higher metabolic rates may be more greatly impacted than larger species. Finally, the intended use of animals must be considered. For example, blood pressure, hydration, blood parameters, stress, and behavior status may be abnormal which may affect research data.

IACUC Recommendations

Species Procedure Type Minimum acclimation Comments
Rodents (Rats, Mice) and Aquatics Non-survival 1 day Use immediately upon arrival may be acceptable, but must be approved in the protocol.
Rodents (Rats, Mice) and Aquatics Survival 2 days  
All other mammals (i.e. dogs, pigs, cats, rabbits, guinea pigs, etc.) Non-survival 1 day  
  Survival 5 days  


Approved: December 2012

Revision Approved: October 2017

Reviewed: April 2020