Carbone, L. 2007. Examining scientific standards. Lab Animal 36(10), 41-43.

On the basis of this paper's conclusions (White et al., 1989), the USDA decreased their cage size requirements and removed the increased space requirement for breeding guinea pigs. How well did the study determine the space needs of guinea pigs? The authors made some unstated assumptions that warrant examination. First, they assumed that the space used by the guinea pigs only 20-25% of the time was not important to their welfare. This could be analogous to concluding that a person's bedroom is not important to his welfare because he spends only 6 hours a day there. The USDA has often ruled that infrequently performed behaviors do not merit legal protection, without questioning whether these behaviors are important to the animal: in 1991, for example, they decided that dogs do not stand on their hind limbs frequently enough to mandate cages tall enough for that behavior. Although some infrequently performed behaviors probably are negligible, others, such as eating a meal, laying an egg or scratching an itch, may be quite important to the animal, despite taking only minutes a day to perform. Data assessment can depend on the purpose for which the standards are being created. If the guidelines focus on human benefit "getting the most out of the mice while using as little space and money as possible" then data concerning growth, reproduction and possibly health might suffice. If the guidelines strive to consider animal welfare, they must focus on indicators of mouse distress, preference, physiology, health and behavior.