Animals in a Vacuum

A recent article addressed the question of what displacement activity is in wild creatures, and offered an answer:

When an animal is in a stressful state, it would sometimes display a behavior that is totally out of context or irrelevant to the situation it finds itself in.

This, the writer says, “may be as a result of two opposing forces — fighting and escape. It may sometimes serve the purpose of averting or diminishing open conflict.”

But if so, why is it described as out of context or irrelevant? Why are “fight or flight” deemed the only appropriate responses, the only reactions that are acceptable to humans as being relevant or in context? Conflict is, after all, ultimately destructive to the species, and if animals have developed a way to avoid conflict, why isn’t that okay with humans?

Why is conflict-avoiding behavior seen as aberrant, rather than rational? The piece goes on:

On the contrary, some zoologists agree that displacement activity is the basis for normal behavioral patterns. Most courtship behavior may be attributed to displacement activities arising from frustrations.

Then, another subject comes up: something called Vacuum Activity, which the author describes as “a behavior exhibited by an animal when no sign stimulus is provided to release the appropriate behavior after its motivation builds up.”

Again, this definition carries a heavy load of human judgment. Who are we to assign meaning to the actions of creatures whose decisions are backed up by thousands of years of evolutionary experience? It does seem rather audacious to decree what is or is not “appropriate” behavior, when it might simply be the case that humans are not as omniscient as we like to believe.

Vacuum activity has been defined and described in different ways. One short page offers this example:

Squirrels that have lived in metal cages without bedding all their lives do all the actions that a wild squirrel does when burying a nut. It scratches at the metal floor as if digging a hole, it acts as if it were taking a nut to the place where it scratched though there is no nut, then it pats the metal floor as if covering an imaginary buried nut.

This seems similar to what others describe as displacement activity, yet in the barren cage, there is presumably no threat that would inspire either fight or flight. So, what are we to make of that? The writer defines vacuum activities as actions triggered by inherited behavior patterns, although without the key stimulus, and to his credit goes on to say,

Vacuum activity is hard to define because it is never certain that no stimulus of any kind triggered the behavior.

There is, at least, a little bit of humility in admitting that the observer is never certain. Likewise, another definition talks about instinctive behavior that occurs “in the absence of the appropriate stimulus.” Yet another says, “This type of abnormal behavior shows that a key stimulus is not always needed to produce an activity.”

These are interesting points, suggesting that scientists may sometimes make unwarranted assumptions about animals’ reasons for doing the things they do. Why do humans get to define what is an inappropriate stimulus, and what is abnormal behavior? They are, after all, discussing actions that are performed by animals in a state of nature. What could be more “normal”? Is it possible that, in all this analysis, there might be a certain element of arrogant presumption?

Even if boiled down to the most common understanding that displacement behavior is something that an animal does when torn between the alternatives of running away or getting into a fight, how are the attitudes that humans express about that justified? Conflict avoidance is a survival strategy beneficial to the individual, their offspring, and the species. Why do we classify it as a perversion?

Your responses and feedback are welcome!

Source: “Displacement Activity in Animal Behavior,”, 02/08/21
Source: “Vacuum activity,”, undated
Source: “Vacuum Activity,”, undated
Image by Jim Bauer/CC BY-ND 2.0

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About Dr. Robert A. Pretlow

Dr. Robert A. Pretlow is a pediatrician and childhood obesity specialist. He has been researching and spreading awareness on the childhood obesity epidemic in the US for more than a decade.
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Dr. Pretlow’s invited presentation at the American Society of Animal Science 2020 Conference
What’s Causing Obesity in Companion Animals and What Can We Do About It

Dr. Pretlow’s invited presentation at the World Obesity Federation 2019 Conference:
Food/Eating Addiction and the Displacement Mechanism

Dr. Pretlow’s Multi-Center Clinical Trial Kick-off Speech 2018:
Obesity: Tackling the Root Cause

Dr. Pretlow’s 2017 Workshop on
Treatment of Obesity Using the Addiction Model

Dr. Pretlow’s invited presentation for
TEC and UNC 2016

Dr. Pretlow’s invited presentation at the 2015 Obesity Summit in London, UK.

Dr. Pretlow’s invited keynote at the 2014 European Childhood Obesity Group Congress in Salzburg, Austria.

Dr. Pretlow’s presentation at the 2013 European Congress on Obesity in Liverpool, UK.

Dr. Pretlow’s presentation at the 2011 International Conference on Childhood Obesity in Lisbon, Portugal.

Dr. Pretlow’s presentation at the 2010 Uniting Against Childhood Obesity Conference in Houston, TX.

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