Hope for bored lab mice
Roxanne Khamsi
Stimulating cages do not affect reliability of experiments.

Studies on happy mice produce results that are just as reproducible as those on stressed animals.

© Alamy

Mice living in exciting environments still produce reliable and reproducible results when used in scientific experiments, according to a new study. The finding suggests that researchers could offer their lab animals more interesting surroundings.

Previous work has shown that mice living in standard, barren cages may suffer greater stress or exhibit abnormal repetitive behaviours1. This uninspired housing has caused concerns over animal welfare, and the validity of experiments. Stress, for example, is known to interfere with learning and memory, as well as the immune system.

But regardless of this, scientists have hesitated to add exciting elements to mouse cages for fear that doing so would influence the precision and reproducibility of test results.

Although the reluctance is widespread, not everyone believes in this logic. "There have been no data substantiating these fears," says Hanno Würbel, an ethologist at the University of Giessen in Germany. He and a team of researchers decided to investigate whether enriched cage environments compromised experimental outcomes.

Engaging ideas

To assess the influence of animal housing conditions, they ran behavioural tests on over 400 female mice. These experiments took place in three different labs and compared standard cages with more exiting ones.

Every few days the researchers introduced novelties such as tunnels, trapezes and tissues into the enriched cages, while the mice living in standard cages missed out.