The laboratory rat is the first animal domesticated specifically for the purpose of science.

Nature · Published 3 October 2026 Swipe more like this →

In short: Long before they were tools for modern medicine, rats were bred for blood sport in 18th-century pits. Today, these rodents are precision-engineered biological models. From their role in mapping human nutrition to their surprising metacognitive abilities, rats remain essential, albeit complex, instruments in our quest to understand human health.

The transition of the rat from a pest to a scientific cornerstone began in 18th-century Europe, where rat-catching was a common trade. By 1828, albino variants—likely descendants of Japanese hooded rats—were being used in fasting experiments. By the early 20th century, researchers like Henry Herbert Donaldson and Elmer McCollum established formal colonies, cementing the rat as a vital model for nutrition, psychology, and genetics.

Unlike wild rodents, laboratory strains are bred for specific traits, such as calmness or susceptibility to certain diseases. The Wistar rat, developed in 1906, became the foundational stock for many modern lines, including the Sprague Dawley and the Long-Evans. These animals are not merely generic subjects; they are highly specialized tools. For instance, the Brattleboro rat helps study kidney function, while the Zucker rat serves as a model for obesity and hypertension.

The utility of the rat lies in its anatomical and physiological parallels to humans. Their aortic arches, for example, share significant structural similarities with our own, making them invaluable for cardiovascular research. Furthermore, their complex brains have allowed for breakthroughs in behavioral science, including the 2007 discovery that rats possess metacognition—a trait previously thought unique to humans and some primates.

Despite their importance, using rats requires extreme caution. A 1972 study revealed that tumor incidence in Sprague Dawley rats varied wildly depending on the supplier, complicating carcinogenicity research. While genetic manipulation in rats has historically lagged behind mice, ongoing advancements continue to refine their role, ensuring that these rodents remain at the forefront of biomedical discovery.

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