To the best of our knowledge, every field of research includes the use of mice and rats in experimentation. There are mice and rats used in research for cancer, genetics, immunology, virology, the behavioral sciences, aging, HIV/AIDS, Alzheimer’s, alcoholism, diabetes, obesity, radiation effects, drug addiction, new drug testing and more. These areas use mice and rats in the questionable hope that what applies to rodents will apply to humans. Perhaps Johns Hopkins toxicologist Dr. Thomas Hartung stated it most succinctly when he said of mice and rats used in research, “We are not 70 kg rats.” Nature did not intend for these animals to be stand-ins for people, and it is not safe to assume that what occurs in rodents will predict what happens in people.
Over the past decade, the number of genetically modified animals has soared globally, with mice and rats used in research for experiments in which genes are added to the animals or “knocked out” in efforts to study gene function. The IMPC (International Mouse Phenotyping Consortium) has a goal of identifying the function of every protein-coding gene in the mouse genome and is working to switch off or ‘knock out’ each of the ~20,000 genes that make up the mouse genome, and have used this process to examine over 9,000 mouse genes so far. There are ongoing efforts to create and utilize knockout rat models as well. Projects such as these have tremendously increased the number of mice and rats used in research and, unfortunately, will continue to do so.
Despite the prevalence of mice and rats used in research by the scientific community, the Animal Welfare Act (AWA), the primary federal law that regulates the use of animals in research, specifically excludes these and other animals, including birds and invertebrates, from the definition of “animal.” Researchers argued that including these animals in the AWA would be a costly administrative burden and exhaust United States Department of Agriculture (USDA) funds and compromise the AWA’s enforcement of protection of other animal species. The result of this omission is that researchers are not required to report the number of these species or how they are used in research protocols to the USDA. As a result, no one knows the exact number of mice and rats used in research in the U.S. every year.
