15/11/2025
"Fear, insecurity, and aggression—the biological basis
There are topics that hardly anyone really wants to talk about, even though they can affect each of us: -Dogs that suddenly growl.
-Dogs that lunge forward out of nowhere.
-Dogs that explode on a leash, even though they are the gentlest souls at home.
And every time, we observe the same thing: people feel ashamed, blame themselves or the dog, and struggle with behavior whose origin they don't even know.
And far too often, quick judgments are made – “dominant", “stubborn", “testing his limits” – phrases that do more harm than good.
Most of the time there is something completely different behind it.
Something deeply biological. Something that every dog carries within himself and that has nothing, absolutely nothing, to do with stubbornness or malice.
Fear, insecurity, and aggression belong together – as parts of an ancient survival system that reacts faster than a dog can even think.
Fear does not begin in the mind, but in the body. The brain sounds the alarm before a dog has a chance to react “rationally.”
The structures that trigger this cascade of alarms – especially the amygdala – work in milliseconds. They evaluate stimuli not logically, but biologically: Threatening or not? Escape possible or not? Can I endure this or must I act?
So when a dog jumps on the leash, barks, growls, or even snaps, it is not acting out of malice. It is acting because its nervous system has long since decided that it is in danger. Long before it even understands why it is reacting at all.
Insecurity is not a character flaw, but a filter. It changes how a dog perceives the world. Many studies describe how stress hormones such as cortisol or adrenaline make perception sharper, faster, but also more distorted.
-A strange dog is not perceived as neutral, but as a risk.
-An unknown person is not perceived as a human being, but as a potential threat.
-A sudden noise is not perceived as part of everyday life, but as a warning signal.
To us, this seems exaggerated – but for the dog, it is reality. And this reality determines its actions.
Aggression itself is almost never the beginning, but rather the end of a long internal chain. Before a dog becomes aggressive, it has sent countless subtle warnings: evasive movements, tense facial expressions, subdued body language, appeasing signals, looks that say, “Please don't come any closer.”
But we humans often overlook this. Not out of malice, but because we haven't learned these subtle nuances. Because we expect dogs to “function.” Because we believe that love is enough to make up for everything. And so it happens that many only react when a dog becomes loud. But that is precisely the last resort. The moment when the dog sees no other choice.
Many dogs react faster and more violently than others – not because they are more difficult, but because their biology has shaped them differently. Genetic factors, breeding lines, early puppyhood stress experiences, malnutrition during pregnancy, lack of or chaotic and too overwhelming , too early socialization – all of these influence a dog's nervous system long before it even arrives in its new home.
Working and Protection Service lines in particular have been selectively bred for decades for reactivity, alertness, and short reaction times. What used to be an advantage often becomes a problem in everyday life today. Added to this are factors that many underestimate: chronic stress, lack of sleep, excessive demands, too many stimuli, lack of opportunities to retreat. And above all: pain.
Modern behavioral medicine studies show that a large proportion of dogs that suddenly become aggressive are suffering from pain or discomfort that has gone undetected for a long time. A dog in pain reacts more quickly and irritably. Not because it is “mean,” but because every stimulus can be too much.
It is important to understand that punishment never cures fear. On the contrary: punishment exacerbates fear. A dog in fear needs security, not harshness. It needs guidance, not oppression. It needs understanding, not pressure. And it needs owners who can read its body language and understand it before it reaches a state where thinking is no longer possible.
We so often hear the phrase, “He has to learn that!” But the problem is not learning—the problem is overload. An overloaded nervous system cannot “learn” while it is in alarm mode. No human being could learn anything new while in a state of fear or stress. No dog can.
What really helps dogs is the opposite of what many people expect: calm, structure, distance, predictability. Rest, and places of retreat. An approach that avoids conflict instead of artificially provoking it. Management is not a weakness—it is responsibility.
And yes, sometimes that means detours, muzzles, distance, training in tiny little steps. But it is precisely these small steps that rebuild the brain. Not pressure, not confrontation, not dominance.
Fear, insecurity, and aggression are not character flaws. They are expressions of an inner struggle that the dog cannot win—not without our help. Many of these dogs are not fighting against us. They are fighting with themselves. With memories, with genetic predispositions, with pain, with inner chemistry that overwhelms them. And yet they try to do the right thing every day. Despite everything.
It is time we stopped seeing these dogs as a “problem” and started seeing them for what they are:
➡️souls that are supposed to function in a world they do not understand.
If we meet them where they really are—biologically, emotionally, physically—then healing can begin. And that is exactly why we are writing these articles:
not to attack anyone.
Not to make owners feel guilty.
But to raise awareness. To make dogs visible before they break. To show that aggression is not malice, but a cry for help. And that every dog that shows fear is a dog that needs one thing above all else:
A human being who sees them. Who doesn't judge them. And who gives them the security that their biology alone cannot provide"
shared and translated from German.
By Dirk and Manuela Schaefer.
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