The subject I was asked to think about with you today is raised by a very large change in the focus of biomedical research. In raw percentage terms, the animals involved in experimentation are now overwhelmingly rats and mice, and, perhaps because they are rats and mice, they are used in large numbers, numbers in thousands and tens of thousands at some institutions. Legal, ethical, and practical accommodation to this fact on the ground presents a host of questions. There are questions of the cost of care. There are questions of the training of veterinarians, principal investigators, and laboratory personnel. With mice particularly, there are questions about the creation of conditions in an animal that do not yet exist, a future animal, by knocking out a gene and, as we say, "seeing what happens": new questions, really, that move us away from the traditional focus on the details of how an investigator treats a living animal. Then there are the central questions of weighing costs and benefits, of justification and the application of the three R's of reduction, refinement, and replacement, where it is not dogs or primates or marine mammals that are concerned, but rats and mice - for many, the least on the scale of concern for animals. Rats, mice, and birds have of course been recently exempted from the Animal Welfare Act. But that may be viewed as making the questions only that much more difficult, thrown back into the laps of researchers themselves and review boards, veterinarians, laboratory assistants, and university and corporate administrators, who for the moment can expect to have that much less outside guidance or mandate in deciding what to do. And I think it is fair to say that lying behind particular responses to questions and resolutions of issues is a newly pressing, overarching problem, which is how to think about rats and mice, not a new problem at all, but newly pressing.
Vining, Joseph. "'The Least of the Sentient Beings' and the Question of Reduction, Refinement, and Replacement." Law Quad. Notes 46, no. 2 (2003): 82-8.