Laboratory mice and rats are derived from a largely nocturnal and climbing ancestor and as such they retain many of the traits of their wild counterparts – exploratory activity, searching for food and climbing. They also like to compartmentalise their behaviours and often use urine marking and bedding to assist.
The Code of Practice for Housing and Care of Laboratory Mice, Rats, Guinea Pigs and Rabbits states:
“Animals must be able to perform a variety of natural activities consistent with species specific behaviour, including the opportunity for sufficient exercise within their enclosure”.
It also states: “The provision of environmental enrichment for mice and rats should mimic natural habitat and behavioural requirements including in particular tunnelling, foraging, climbing, social groupings and nesting.”
The current minimum standards, where these animals are kept in small containers, cannot accommodate the innate behavioural needs of a naturally foraging animal, nor allow for sufficient environmental enrichment.
For more information, download our fact sheet:
Bulletin 9 – Rats and Mice – Maligned & Misunderstood

Bred for Brain Damage
A 2025 study bred rats over multiple generations for seizure susceptibility—but failed to create a working epilepsy model, highlighting the limitations of animal experiments and

Intermittent Fasting in Mice
Research paper Intermittent fasting increases energy expenditure and promotes adipose tissue browning in miceNutrition 2019 Oct; 66:38-43. doi: 10.1016/j.nut.2019.03.015. 2019https://pubmed.ncbi.nlm.nih.gov/31207437/Bo Liu , Amanda J Page

Mice forced to inhale e-cigarette vapour during pregnancy
Research Paper: Maternal E‑Cigarette Exposure Results in Cognitive and Epigenetic Alterations in Offspring in a Mouse Model (2018) http://dx.doi.org/10.1021/acs.chemrestox.8b00084 Tara Nguyen, Gerard E. Li, Hui

Australia’s TBI Research on Animals
Australian universities are routinely causing traumatic brain injury (TBI) in rats and mice by dropping weights, or via invasive procedures to create fluid in the