Lab Rat's Pinker and Relaxed Ears Tell Us They're Feeling OK
New research shows there are facial indicators of positive emotions in rats.
Posted December 7, 2016
I'm always looking for interesting studies about which to write, and today, one came across my desk by researcher Kathryn Finlayson and her colleagues called "Facial Indicators of Positive Emotions in Rats." It's been well established by detailed research that rats experience positive emotions and enjoy playing and being tickled, and they also laugh.
The abstract for this essay, available online, reads:
Until recently, research in animal welfare science has mainly focused on negative experiences like pain and suffering, often neglecting the importance of assessing and promoting positive experiences. In rodents, specific facial expressions have been found to occur in situations thought to induce negatively valenced emotional states (e.g., pain, aggression and fear), but none have yet been identified for positive states. Thus, this study aimed to investigate if facial expressions indicative of positive emotional state are exhibited in rats. Adolescent male Lister Hooded rats (Rattus norvegicus, N = 15) were individually subjected to a Positive and a mildly aversive Contrast Treatment over two consecutive days in order to induce contrasting emotional states and to detect differences in facial expression. The Positive Treatment consisted of playful manual tickling administered by the experimenter, while the Contrast Treatment consisted of exposure to a novel test room with intermittent bursts of white noise. The number of positive ultrasonic vocalisations was greater in the Positive Treatment compared to the Contrast Treatment, indicating the experience of differentially valenced states in the two treatments. The main findings were that Ear Colour became significantly pinker and Ear Angle was wider (ears more relaxed) in the Positive Treatment compared to the Contrast Treatment. All other quantitative and qualitative measures of facial expression, which included Eyeball height to width Ratio, Eyebrow height to width Ratio, Eyebrow Angle, visibility of the Nictitating Membrane, and the established Rat Grimace Scale, did not show differences between treatments. This study contributes to the exploration of positive emotional states, and thus good welfare, in rats as it identified the first facial indicators of positive emotions following a positive heterospecific play treatment. Furthermore, it provides improvements to the photography technique and image analysis for the detection of fine differences in facial expression, and also adds to the refinement of the tickling procedure.
All in all, pinker and relaxed ears tell us that rats are experiencing positive emotions, that the researchers' claim means the rats are experiencing "good welfare." I think this is a very important study and supports other research in which it's been shown that a cow's ears also tell us how they're feeling (please see "The Emotional Lives of Cows: Ears Tell Us They're Feeling OK") as do their noses (please see "The Cow's Nose Shows How They're Feeling About Life").
What is "good welfare?" "Good welfare" does not mean a rat is having a "good life"
Dr. Finlayson and her colleagues write, "This study contributes to the exploration of positive emotional states, and thus good welfare, in rats as it identified the first facial indicators of positive emotions following a positive heterospecific play treatment." So, rats like to play, and, as a result, their ears get pinker and more relaxed and they emit more positive ultrasonic vocalizations. But, does experiencing a positive emotional state equal good welfare? And, what does "good welfare" mean, especially for an individual rat. Experiencing good welfare does not mean that a rat (or other animal) is having a "good life." It only means that they may be feeling better than another individual who is having a bad day, or many bad days.
Rats and mice are not animals under the current federal Animal Welfare Act: Bridging the knowledge gap
I hope that the results of this study, when added to the wealth of data we currently have on the emotional lives of rats, will result in an immediate revision of the current Federal Animal Welfare Act in which laboratory rats and mice are not considered to be animals. The science that clearly shows these rodents are sentient beings continues to be totally ignored. Thus, in the 2002 iteration of the AWA we read one of the most idiotic statements I can find about these smart and sentient beings, namely,
"Enacted January 23, 2002, Title X, Subtitle D of the Farm Security and Rural Investment Act, changed the definition of 'animal' in the Animal Welfare Act, specifically excluding birds, rats of the genus Rattus, and mice of the genus Mus, bred for use in research."
The first time I saw this I had to read it a few times to be sure my eyes were still working. They were and are. This exclusion of rats and mice from the animal kingdom is pure idiocy, and few if any researchers are doing anything to change this example of "bad biology" (please see "The Animal Welfare Act Claims Rats and Mice Are Not Animals").
Let's celebrate the 50th anniversary of the Animal Welfare Act by immediately placing rats and mice back into the animal kingdom. And, let's tighten up all legislation so that the lives of all individual animals are well protected from abuse. It's high time to replace the science of animal welfare with the science of animal well-being in which the life of each and every individual matters so that they can live free of pain, suffering, and death. It seems laughable that rats, mice, and other animals aren't considered to be animals in the latest iteration of the Animal Welfare Act, but it is not! It's a tragic sham that results in horrific pain, suffering, and death "in the name of science" and, some rightly say, "in the name of money."
Where are all the scientists who know that rats and mice are sentient animal beings? Why aren't they protesting the idiocy of the AWA?
A much-needed call to action. Before people pat themselves on the back and claim that things are just fine, and better than they were years ago for the billions of research animals who suffer and die at our hands, I hope people far and wide will call for an immediate and thorough revision of the Animal Welfare Act and other legislation that takes into account the results of detailed research, and that researchers themselves will actively partake in the process of restoring rats, mice, and other animals to the animal kingdom, the place where they clearly belong. Indeed, researchers should mandate an immediate biologically based corrective to the AWA and openly lead the way.
We must close the knowledge gap and use what we know from detailed comparative research to protect other animals
Focusing on rodents for now, it's high time to "reclassify" rats of the genus Rattus and mice of the genus Mus as animals, for they surely are, and for calling for the termination of invasive and abusive research on these sentient beings. Laws and regulations for protecting other animals from harm, suffering, and death must keep up with the latest science, and we've known for years that those rodents, and many other animals who are routinely used and abused in research, suffer not only their pains but also those of others. So too do "food animals" and "fashion animals," and those sentient beings who are used for entertainment and who suffer immensely to make us laugh.
There is no reason for rats, mice, and other animals to be "left out in the cold," as Daniel Engber puts it in his essay called "Some Animals Are More Equal Than Others." We must close the knowledge gap and use what we know from detailed comparative research to protect other animals.
Science could save millions upon millions of animals, but it's not doing a very good job at doing so. After rats and mice and other animals are properly classified, we can work to stop using them altogether. As their use in horrifically painful research is phased out, we are obliged to do all we can to allow them to experience positive emotions, that in plain jargon means we are obliged to make them as happy as they can be in situations that severely compromise their lives and in which they experience a whole host of enduring negative emotions.
Surely, we can do much better for individuals of numerous species who continue to be used in invasive research as if they're disposable objects. I hope researchers will get actively involved in correcting the idiocy of the current version of the federal Animal Welfare Act. It's long overdue and it's high time they did. A rat's ears tell us a lot about what they're feeling and we must use this information on their behalf.
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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 early 2017.