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This essay was written with Psychology Today writer and bioethicist, Dr. Jessica Pierce
For a long time, researchers have been concerned with how data collected on captive animals actually transfer over to the behavior of wild relatives. While certain patterns of behavior are shown both in captive and wild members of a specific species, captive conditions can be stressful and produce unreliable and non-replicable results. A recent analysis by Michaël Beaulieu, published in a paper called "A Bird in the House: The Challenge of Being Ecologically Relevant in Captivity," shows just how true this may be.
Dr. Beaulieu's essay is available online so here are a few snippets to whet your appetite for more. The abstract for his study reads as follows:
Ecologists have acknowledged the fact that environmental conditions strongly affect life-history strategies in the wild. However, when working in captivity, they appear to overlook these effects. This approach appears precarious, as it likely contributes to increase the inconsistency of results across ecological studies. To illustrate this point, I reviewed here the conditions under which captive zebra finches (Taeniopygia guttata) are kept in studies examining stress parameters that mediate life-history strategies, and compared these conditions to the conditions their wild counterparts experience in their native habitat. I found that captive zebra finches are typically kept under conditions that mostly reflect a paradoxical season in terms of temperature, light and humidity that would never be encountered in the wild. Most importantly, I also found that these conditions are associated with elevated stress levels. This suggests that most studies using captive zebra finches are conducted under stressful conditions, and therefore give a biased and limited view of how birds regulate life-history strategies. This example strongly suggests that we have to rethink our approach when examining ecological questions in captivity, by carefully considering conditions under which animals are kept in view of their current and future ecology.
Dr. Beaulieu considered a number of different questions including:
Do Conditions in Captivity Reflect Natural Conditions? They don't.
Are Conditions in Captivity Stressful? They are, and sleep disruption appears to be a major contribution to stress.
What Are the Consequences of Keeping Captive Animals Under Stressful Conditions in Ecological Studies? Dr. Beaulieu concludes, "most behavioral studies also only give a biased and limited view of the full behavioral spectrum of these birds. Such concern has already been raised in neurobiological sciences (Schmidt, 2010)."
Why Do Investigators Use Such Conditions in Captivity?
The overall conclusion of Dr. Beaulieu's analysis is "ecological studies often overlook the effects of environmental conditions on the regulation of life-history strategies in captive animals ... thereby casting doubt on the generality of findings (Speakman et al., 2015)."
He goes on to write, "investigators need to be aware and acknowledge that these conditions are stressful (and not try to dismiss this fact). Consequently, when deciding about which conditions to use in captivity, the main question should be: are the parameters representative of the natural conditions encountered by animals in space and time, and is this combination of parameters stressful? Only this simple but more rigorous approach will allow us to reconcile ecological studies and captivity."
Better welfare = better data
While some of these cautionary statements are not new, we hope more and more researchers will take them to heart. Keeping animals in suboptimal conditions is a welfare concern, and a growing number of researchers agree that better welfare = better data. In our forthcoming book titled The Animals' Agenda: Freedom, Compassion, and Coexistence in the Human Age, we write (p. 86), "One of the things that animal researchers have discovered, over and over again, and which is a boon to the research animals themselves, is that better welfare equals better science. This has been the main impetus for improving lab-animal welfare ... Animal sciences professor Joseph Garner (note 1, p. 106) writes, 'It is useful to think of behavior as an organ, which is integrated with the biology of the whole animal . . . behavior is intimately involved in homeostasis.'" In other words, alterations in behavior have effects on physiology, which in turn have effects on the validity, reliability, and replicability of scientific outcomes.
There are myriad ways in which compromised welfare results in compromised science. Just recently, for example, a group of researchers at the US National Institute on Aging in Bethesda, Maryland, expressed concern that many rats and mice used in experimental studies are so overfed they may die prematurely, and that such premature deaths may skew data collection in areas as diverse as immune function, cancers, and neurological disorders (Daniel Cressey, 2010). A New Scientist article by Ann Baldwin and me, “Too Stressed to Work,” cites research on rats housed in stressful conditions. Rats “show an inflammatory response in their intestines accompanied by leaky blood vessels. . . . As a result, the gut’s defence barrier breaks down, leading to chronic inflammatory conditions such as ‘leaky gut.’ This inflammation adds uncontrolled variables to experiments on these animals, confounding the data.”
Another recent study, published in Trends in Cancer, noted that even something as subtle as air temperature in the laboratory can induce stress in animals and can, in turn, affect data. Immunologists Bonnie Hylander and Elizabeth Repasky have been investigating the effects of cold stress on the mouse immune system. Labs are often kept fairly cool, since researchers wear robes, gloves, and masks and can become quite warm while they are working. Yet Hylander and Repasky found that the cold temperatures also affect the mice, whose heart rate and metabolism change as their bodies try to generate heat. Tumors grow more quickly, metastasize more quickly, and respond less well to chemotherapy in mice who are cold than in mice whose bodies are warm. The researchers are concerned because reported data don’t generally take into account ambient temperatures in the laboratories where the research was conducted and the data may, therefore, be misleading. (reference 4)
Indeed, and this is the frightening part: there are likely lots of ways in which data are skewed of which we aren’t even aware. All the while, this is not only bad for the animals but bad for people. The interactions of poor welfare, unseen sources of stress, and the nuances of the parameters being measured, not to mention subtle differences in behavior and physiology that each individual animal brings to the table, all combine to create a perfect storm and we must be very careful to emerge from this storm with reliable scientific data.
Stress Essential Reads
Our purpose here is simply to call attention to the fact that studies on captive animals who are living under unnatural conditions and unknowingly stressed can produce misleading results and it's not surprising that different research groups have difficulty replicating the data from other labs. Is this the reason why so many drug tests that pass on nonhuman animals fail to work on humans? It may well be, and this adds to the concern that people put too much weight on data collected on captive animals as if they are reliable indicators either of how their wild relatives behave or how the results can be applied to humans.
The bottom line is that researchers need to be extremely careful about drawing conclusions from data collected on captive nonhuman animals, and that stress and other obvious and not so obvious factors can influence data to the point that they are relatively useless.
References
Ann Baldwin and Marc Bekoff, “Too Stressed to Work,” New Scientist 9 (2007): 24, .
Daniel Cressey, “Fat Rats Skew Research Results,” Nature 464 (2010); Bronwen Martin et al., “‘Control’ Laboratory Rodents Are Metabolically Morbid: Why It Matters,” Proceedings of the National Academy of Sciences 107 (2010): 6127–33, doi:10.1073/pnas.0912955107.
Garner, Joseph P. “Stereotypies and Other Abnormal Repetitive Behaviors: Potential Impact on Validity, Reliability, and Replicability of Scientific Outcomes.” ILAR Journal 46 (2005): 106–17.
“Are Lab Mice Too Cold? Why It Matters for Science” ScienceDaily, April 19, 2016,
Marc Bekoff's latest books are Jasper's Story: Saving Moon Bears (with Jill Robinson), Ignoring Nature No More: The Case for Compassionate Conservation, Why Dogs Hump and Bees Get Depressed: The Fascinating Science of Animal Intelligence, Emotions, Friendship, and Conservation, Rewilding Our Hearts: Building Pathways of Compassion and Coexistence, and The Jane Effect: Celebrating Jane Goodall (edited with Dale Peterson). The Animals' Agenda: Freedom, Compassion, and Coexistence in the Human Age (with Jessica Pierce) will be published in April 2017 and Canine Confidential: An Insider’s Guide to the Best Lives For Dogs and Us will be published in early 2018. Jessica Pierce's latest books are The Last Walk: Reflections on Our Pets at the Ends of Their Lives and Run, Spot, Run: The Ethics of Keeping Pets.
