In 2003, the sociologist, Lynda Birke published an article entitled Who or What are The Rats and Mice in the Laboratory? That question forms the framework for this discussion in which we'll consider the status of animals used in biomedical research. We'll use the example of mice because they are used most commonly. We'll see how they become less like animals and more like tools. To begin, let's consider the numerous roles and labels we assign to mice. A mouse can be a pet, in which case he or she has a name and is considered an individual. When a pet mouse dies, a burial may occur, perhaps in the garden and complete with mourners. In such cases, at least some members of the family experienced the event as a loss. In other instances, mice are seen as pests. They eat food meant for humans, they spread disease that threatened humans. These mice have no individual names. They sometimes die by poisoning. Other times they die in ineffective but commonplace snap traps. These break bones but seldom deliver enough force in the right place to result in death or they die on sticky traps caught on strong adhesive, and their struggles to escape only caused more of their body surface to adhere. Treating a dog, cat, or other animal to a death by poison or entrapment would constitute cruelty. But no one mourns or objects to the deaths of mice considered pests. Neither does anyone mourn the deaths of mice raised to feed carnivorous species such as snakes and some lizards and toads. Most snakes must eat live prey. Feeder mice can be adults, juveniles, or newborns, called pinkies. This raises moral issues involving the competing interests of two animals who can hold the same status as pets. To feed the snake, the mouse must die. If the mouse lives, the snake will starve. The mouse's fate depends on whether we consider him or her food or pet. The people who feed the snake might feel disgust or fascination about the act of feeding live prey, but no one who grieves for the mouse can care for snakes for very long. The mouse most commonly used in laboratories is the white mouse, the albino strain of Mus musculus. During the 19th century breeding craze that also gave us most of today's dog and cat breeds, amateur rodent enthusiasts spread fancy strains from wild mice, usually selecting for coat color. Early in the 20th century, a Harvard graduate student named Clarence Cook Little, obtain a pair of mice with well-documented bloodlines and began breeding them for his research on genetics. Mice reach sexual maturity around six weeks of age. They have litters of at least four and as many as 10 pups, and they can easily produce a dozen litters per year. Their reproductive capacity made them the species of choice for studies of mammalian genetics. Clarence Little bred brother to sister for over 20 generations and selected the most vigorous offspring. By using inbreeding techniques, he engineered strains that frequently developed cancerous mammary tumors. In addition, the mice spread quickly enough to observe the diseases' generational course, and through inbreeding, they had stable genetic material that eliminated unwanted variability. Inbred mice soon became the standard for cancer research. Because mice are mammals, scientists presumed that diseases in mice followed courses similar to those that affect humans. Mice became a morally acceptable stand-in for humans in medical research. Researchers created distinct strains of mice for a specific research applications. The growth of molecular biology created even greater demand for mice because of the relative ease with which their genes can be modified. For example, what's called a knockout mouse has a particular gene inactivated, so that the mouse consequently has the behavior, appearance, or biology of an individual who lacks that gene. Genes from other species, including humans and even jellyfish, can be inserted into mice. Breeders develop specific pathogen-free mice, which had none of the bacterial or viral pathogens carried by conventional mice. These mice are delivered by C-section. The mother is killed in the process. The sterile uterus is placed in a sterile environment. Scientists can then infect the fetuses with just a single microbe, allowing for the study of the effects of that one organism. Scientists engineered transgenic mice by altering embryos with genes that produce a trait of interest, such as a predisposition to develop human breast cancer. In short, the production of mice for laboratories has become a huge industry. Along the way, the rodents used in research lost their statuses, individual animals and instead became data or equipment, what one scholar called test tubes with tails. They moved from being animals as understood in the wider culture, to being tools of the trade, part of the apparatus of science. As creatures designated as "lab animals", they have no counterparts in nature. They've been transformed from what most of us would commonly call an animal into something that stands for data and scientific analysis. In addition, the mice used in research aren't even legally considered animals. In the United States, The Animal Welfare Act excludes birds, rats, and mice bred for use in research from regulation. Notably, the Act excludes the very animals researchers have created. Finally, there have always been ethical questions about the use of animals in experiments. The principles that have guided animal research are known as the Three Rs. Researchers should refine procedures to minimize pain and suffering, replace animal subjects with non-animal alternatives where scientifically feasible, and reduce the number of animals used in experiments. The Three Rs aim to minimize animal suffering in ways that still permit research. However, with the growth of the biotechnology industry, mice and rats are being produced in greater numbers. In some, alongside the stated goal to decrease the use of animals, the trend has been more of them, by not recognizing most of them as animals.
