A white Severe combined immunodeficiency (SCID) mouse. Charles River Laboratories, in collaboration with Tufts University, share why lab mouse happiness is so important.Photo courtesy of National Cancer Institute via Wikimedia CommonsAs part of their effort to improve drug development, Charles River Laboratories, in collaboration with Tufts University, has found a new way to measure mouse wellbeing by observing nesting behavior, or the act of the mouse building a nest. Levels of nesting behavior are a simple way researchers can evaluate a mouse’s wellbeing because a healthy, content mouse will instinctually nest to improve its fitness and survival.

The new wellbeing test and results, published in a study this month in the Journal of the American Association for Laboratory Animal Science, demonstrate how a simple and quick diagnostic screening tool—dubbed the time-to-integrate-to-nest test or “TINT”— was able to determine which mice were healthy, and which had compromised welfare and needed further attention.

To view a short video of a high-scoring mouse nesting and read the full blog, visit www.criver.com.

Study author Brianna Gaskill, a postdoctoral research scientist at Charles River Laboratories whose past studies include the importance of keeping lab mice warm, is available for interviews. A longer video of the TINT test is available on the Journal of Visualized Experiments (JOVE).