THE TORMENT OF ‘OTHERS’: What can caged lab monkeys tell us about free human beings?
Scientists know that the confinement of animals in laboratory cages distorts the psychology and physiology. Yet, despite a half-century of evidence, we continue to cage them. They might have more in common with children housed in Romanian orphanages in the 1980s and 1990s, who were so deprived of human contact that they still struggle with lifelong physiological and psychological disabilities.
GARET LAHVIS: After publishing more than 40 scientific papers, I left academia. In part, I left on principle. I believed that if we experimented on animals, we were obligated not to waste them. I also believed that biomedical scientists were obliged to consider the implications of our own discoveries — like how our animals were responding to their cage environments — so we could do better science. Eventually, I lost faith in the process. I also lost the stomach to confine sentient creatures to tiny cages.
Scientists know that the tight confinement of standard laboratory cages distorts the psychology and physiology of our animal subjects. Yet despite a half-century of evidence, we continue to cage them as if their biology is baked into their genetics. From decades of rodent studies, scientists know that an animal’s brain anatomy and physiology are highly vulnerable to even modest changes in their living environments.
Mice housed in standard cages, rather than slightly larger ones furnished with blocks and tunnels for mental stimulation, are more susceptible to drug abuse, genetic modifications, and toxic chemicals. Monkeys, nearly our next of kin, can become so mentally deranged by their cage environments that they no longer resemble healthy humans. They might have more in common with children housed in Romanian orphanages in the 1980s and 1990s, who were so deprived of human contact that they still struggle with lifelong physiological and psychological disabilities…
Globally, scientists use approximately 100,000 non-human primates at any given time, often to explore highly nuanced questions, like finding risk factors and treatments for mental health challenges — autism, ADHD, schizophrenia, addiction, anxiety, depression, post-traumatic stress disorder. And here, we mostly fail. Most drugs showing extreme promise in animal studies fall short in human trials…
Scientists also use primates to understand how human-like immune systems respond to infectious diseases — but, like mental health, immunity is also highly sensitive to how the monkeys feel inside their cages. Housing for monkeys is tight. The standard cage for a rhesus macaque, a common laboratory primate, is about 2.5 feet across, narrow enough for its inhabitant to touch both walls at once. By contrast, their wild relatives can navigate home ranges averaging about 1.5 square miles. Macaques are built to navigate 740 American football fields’ worth of savannah grasslands and forest canopies. Yet inside biomedical labs, they typically get confined to the equivalent of a telephone booth…
Lab monkeys express behaviors that suggest psychological trauma. Among 362 singly housed rhesus monkeys, a study found that 89 percent expressed abnormal behavior. Most were what we call “stereotypies” — repetitive behaviors that serve no purpose, save coping. Some monkeys pace in circles. Others rock or bounce for hours, like idling engines. Some methodically somersault. Others incessantly rattle their squeeze bars. A few spend time in “eye salute,” a euphemism for self-stimulation by sticking fingers into one’s own eye…
Up to 15 percent of laboratory monkeys self-mutilate. They might pluck single hairs from their backsides until they turn bright pink, or bang their heads repeatedly against their cage walls, or bite themselves deep enough to require sutures. Unlike their wild brethren, caged macaques often paint the walls with their feces — a substance they can manipulate. Nearly one-quarter of caged macaques express “floating limb” behaviors…
These behaviors are manifestations of an intolerable allostatic load: a “wear and tear on the body and brain resulting from chronic overactivity or inactivity of physiological systems that are normally involved in adaptation to environmental challenge.” Cramped living spaces deny primates the ability to act on their innate motivations: to seek pleasures, avoid discomforts, and explore complex and changing environments…
Curiosity is also an innate drive. In the wild, animals feel compelled to investigate their environments — where to go, what to eat, with whom to interact — to know their options when their situations change… deprived of varied and ongoing challenges to overcome, environments to explore, or a natural range of body movements, caged monkeys — studied because they resemble us — go insane with boredom…
Admittedly, scientists are in a fix. Our problem might have begun during the late Middle Ages, about 800 years ago, when Italian philosopher and theologian Thomas Aquinas argued that because animals lacked “rational souls,” they were like machines…
The cruel irony is that the ethical justification for experimenting on animals — that they lack subjective experiences — allowed us to find cogent evidence that they do. Now we’re forced to ignore what we’ve learned from science — so that we can keep doing it.
Rather than envision a new paradigm, scientists have devised arguments to keep things the same, claiming, for example, that we need small cages to control for confounding variables in an animal’s environment. But we routinely accept the inescapable variables inside their confines — sound, lighting, food quality, social situations — that are either impossible or too inconvenient to control. In truth, we use small cages because they afford the cheapest and most convenient way to generate scientific publications…
What could scientists do differently? We could pivot to more helpful alternatives. We could deploy spatially and temporally complex spaces to study smaller organisms under conditions where they might thrive like the free human beings they are meant to resemble…
With advanced epidemiological computer modeling, and gene sequencing tools, along with high-efficiency cell culture systems that can test multiple chemicals at a time without the use of animals, we could identify harmful compounds, then remove them. The potential is far greater than whatever we might learn from using rubber snakes to scare mentally enfeebled monkeys. SOURCE…
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