Consider the Mouse

  The American species of the common house mouse (Mus musculus) does an odd thing when going through opiate withdrawal. Above and beyond what we would call normal mouse behavior—such as defecating, urinating and sniffing indiscriminately—a spectator in the odd position of happening upon a mouse enduring opiate withdrawal would see the mouse jumping involuntarily, rearing up on its hind legs and leaping 3-4 feet in the air[1]. I found myself in that exact disturbing position this summer, while interning at a research hospital in New York City.


           On the bottom floor of said research hospital is what trained doctors affectionately call the ‘Mouse House’. After exiting the elevator at the innocuously labeled B5 stop, I walk into an intermediate holding room in which I don scrubs and gloves and proceed through a hyperbaric air chamber into a fluorescently lit hallway. The corridor smells overwhelmingly of (what I come to learn is) a mix of rodent food, urine and sawdust material that lines the bottom of the mouse cages. The smell is not entirely unpleasant.

           Jutting off of the main hallway there is a maze of corridors, each with key card clearance points; the end of each corridor reveals an airtight room (further key card clearance required) equipped with rows of shelving lined with mouse cages. Each corridor also contains refrigerators containing mouse brains marked for analysis and bookshelves-turned-mouse-graveyards affectionately called ‘Sack Racks’. (I was unable to ascertain with any level of certainty whether rhyme was one of the coping mechanisms doctors employed to beat back their moral qualms about the high rodent mortality rates in the Mouse House.) Normal protocol involves a brief stop at the Sack Rack before the day’s experiments, the onlooker wearing an expression somewhere between that of an executioner hardened to the ways of death and that of a small child fascinated by it.


           Mice in the Mouse House live an abnormally comfortable life—relative, at least, to the majority of the Mus musculus species. Cages are filled with ample food and water and cleaned daily. No more than 5 mice are allowed in a given cage, and those which display an aggressive demeanor or a susceptibility to bullying are placed in solitary confinement, accompanied by special color coded rap sheets explaining the reason(s) for which they have been separated.

Of course, the one drawback to the relatively comfortable life these mice lead is the experiments performed upon them. In my case, this involves injecting mice with novel opiate compounds and testing for analgesia and drug tolerance through a behavioral test called the Tail Flick Assay.[2] These are relatively non-invasive tests and the mice endure them without too much apparent discomfort.

Talking about quality of life for these mice, though, is already a tricky subject, since the only reason these mice are alive is for scientific research. The mice are genetic variants bred so as to be useful for research. There is a real teleological purpose to their life and death in the pursuit of science. Or so I tell myself when placing mice in CO2 chambers and then cervically dislocating their spines so as to access their brains for further analysis.


           But naturally moral qualms become more pronounced as a minor mouse genocide begins to rest solely on my conscious. Certain questions become unavoidable. Is it morally acceptable to inject compounds with unknown physiological effects into sentient beings, who are later killed in the name of science writ large? Is the previous question irksomely PC or sentimental?

Members of People for the Ethical Treatment of Animals would have you think that all of this is inhumane and immoral and just downright bad. Presumably, the moral thesis promoted by PETA activists is one about pain, discomfort and death; in some fundamental way the employment of sentient mammals as the primary testers of compounds of unknown effect and the subsequent pain and death inflicted upon them is wrong.

And in fact, the research hospital at least implicitly admits that to the untrained eye, the Mouse House looks bad. I was twice admonished for trying to take a picture of the Mouse House[3], wagging fingers pointing to the signs of an old fashioned camera with a red ‘X’ through it.

So how do we begin to even tackle the morality of the use of animals for scientific research?


           First, let’s admit that questions of how different kinds of animals experience pain, and of whether it might be justifiable to inflict pain on them in order to make scientific discoveries, turn out to be extremely complex and difficult. As David Foster Wallace explores in his essay “Consider the Lobster,” even defining what counts as pain is difficult, since pain is mainly a subjective phenomenon. There are easily recognizable objective indications that signal pain to an observer, but even so, deciding what does and does not count as an objective indication of pain and how we ought to respond to these indications are questions of hard-core philosophy—metaphysics, epistemology, ethics, value theory.

As a test just think about watching a friend of yours squashing a cockroach on the ground and seeing it writhe in pain. Next switch that to a lizard; now a mouse; now a dog; now a human. If you are a ‘normal’ person, my guess is that you have a different gut moral response as you imagine each hypothetical situation. (Hopefully one of increasing disgust, such that by the time your friend is squashing another human you have decided that you need to pick your friends more wisely). But the question of why you feel so differently about a bug’s pain and a mouse’s and a human’s is the stuff that philosophers find so interesting, especially because by the time you get to a mouse (or any mammal for that matter), the neuronal pathways that constitute pain are more or less the same as any human’s[4].


Most ethicists hold that there are two criteria that determine whether or not an animal has the capacity for suffering—and thereby warrants  our moral consideration[5]. The first is neurological: does the animal have the hardware required for the experience of pain? The second is behavioral: does the animal behave in such a way as to indicate the experience of pain is occurring?

           Now most animals (from bug to human) fulfill the first requirement. Pain reception is part of an extremely old and evolutionarily beneficial neuronal pathway managed by nociceptors and prostaglandin receptors. This is what controls our unconscious, instinctual reaction to pain. It is why, for example, we pull away immediately after touching the electric stove we had believed was off[6].

The second criterion is more about an animal’s experience of pain, controlled in humans and mammals by the cerebral cortex. The cerebral cortex allows us to associate stimuli with a feeling of distress or unpleasantness. It allows for an experience of pain beyond just instinctual response. It is why we know in some intellectual sense that touching a fire will be emotionally unpleasant for us.

After all the abstract intellection, I'm left with the image of mice showing clear signs of distress and discomfort, throwing themselves into the air because of a drug that yr. correspondent makes and injects into them. This is, by any ethicists definition, pain not so unimaginably different from your own. The mice have an interest in ensuring that this is not done to them. In fact, experimenters often have to switch mice they work on as soon as the smell of an experimenter becomes familiar; mice eventually begin to make efforts to avoid the inevitable discomfort they associate with the smell of the experimenters becoming much harder to handle.

These are realities of modern science. What I believe to be necessary evils involved in the pursuit of better human life. My initial reaction to PETA activists then, is that they are extreme. And yet the reason their position seems extreme to me appears to be based on some unsubstantiated belief that animals are in some way less morally important than human beings. That is, mouse suffering and death is justified by as little as the possibility of making scientific breakthroughs that could help human life.  

But even asserting this belief, forces me to acknowledge that it belongs to a self-interested personal ethical system that I may not be able to justify. I have only a vague notion that this belief is truly defensible rather than merely selfishly convenient. For now though—with so much mouse death and suffering already on my hands—this self-interested belief may have to suffice[7].

[1] And they say white mice can’t jump.

[2] In which a mouse’s tail is subjected to increasing heat, and the time at which it flicks its tail away is recorded. This is a way to see if the opiate drug is producing analgesic effects.

[3] Instagram opportunities everywhere you look!

[4] This is, of course, why mice are used in scientific research on pain and pain medication.

[5] See, for example, Peter Singer’s Animal Liberation, and David Foster Wallace’s “Consider the Lobster”

[6] This is, admittedly, a very rough sketch of the pathway involved in this reaction.

[7] I’m indebted to David Foster Wallace for his brilliant essay Consider the Lobster, by which I was inspired to write this piece.