There's a Major Issue With How We Treat Lab Mice, And It Could Affect Study Results - ScienceAlert

Over 120 million laboratory rats and mice are used worldwide each year.

The studies we synthesized all compared conventional "shoeboxes" – the small, barren cages typical in labs – with better-resourced housing containing running wheels, nest boxes, additional space or other items that allow natural behaviors like digging, climbing, exploring and hiding.

Across the board, the animals in conventional cages became sicker than ones in better-resourced housing.

Scientists have known for decades that rats and mice want more comfort, exercise and stimulation than is normally provided, and that conventional cages therefore induce abnormal behavior and anxiety.

Furthermore, despite investigating housing effects, two-thirds of the studies in our analysis did not fully describe animals' living conditions.

Our findings support many previous suggestions that rats and mice living in barren cages that lack stimulation may not be suitable models, for several reasons.

The "shoeboxes" that rats and mice currently live in should stop being ignored as if a neutral backdrop, and instead be seen as a determinant of health: one we can modify, improve and study.