Why are Rats Used in Research?

Rodents have long been the preferred species of lab animals in biomedical research, with sporadic experiments on common brown rats stemming back 150 years. Though laboratory animal research continues to pose ethical questions, particularly with respect to animal welfare, the scientific achievements linked to lab rats are innumerous. This primarily relates to the extraordinary anatomical, genetic, and physiological similarities between humans and rodents. Yet there are many additional reasons beyond human and animal similarity why the so-called wild Norway rat, Rattus norvegicus, is such a perfect candidate for research communities.

A Quick History of Rat Research

The Norway rat, equally referred to by names as varied as the Hannover rat, common rat, street rat, and wharf rat, is widely considered to be the earliest mammal domesticated for research purposes. First in a storied line of documented studies involving lab rats was an observation of the effects of adrenalectomy (Philipeaux, 1856), followed by a study on protein nutritional quality (Savory, 1863). Domestication of the Norway rat has since led to many distinct genetic lines which have been carefully bred for specific purposes.

There is subsequently no universal rat model for all laboratory research, but a plethora of inbred/outbred stocks and strains suited to specific purposes. The Wistar outbred albino rat is perhaps the most popular rat model due to its multi-purpose characteristics, making it a powerful species for medical research into infectious diseases, or as a surgical model. Then there is the Sprague Dawley, an outbred albino preferred for behavioral studies.

This extreme population variety is part of what makes rat research so attractive. But the ability to produce so many strains is less a story of scientific ingenuity and more a credit to the incredible adaptability of an animal that is still largely vilified as a pest.

What Makes Rats Ideal for Research?

The same versatility that makes rats such a prolific species in the wild helps them to thrive in captivity. They can readily survive in some of the most adverse conditions and have a nearly unparalleled ability to reproduce. Their extremely short reproduction cycle and ready availability translates to dramatically low cost of breeding, which is compounded by their high survival rates in captive environments. In many ways, it is the uniqueness of rats, rather than their similarities to humans, that make them such an ideal resource in laboratory settings.

Read More: Mice Vs. Rats in Research: What’s the Difference?

There is an argument that lab rats have degenerated from the wild species to the extent that captive populations have lost some of their value as a model. Though there is little cause for concern regarding the advanced domestication of lab rats, there is an argument for the resumption of studying wild species alongside the extremely specialized models obtained through decades of controlled genetic mutation.

If you would like to learn about how researchers ensure animal welfare throughout critical rat research, refer to our articles on rodent physiological monitoring.

Sources:

https://elifesciences.org/articles/50651#s7