Predator, Prey, and the Fear System in the Wild

I want to share two nature videos that vividly demonstrate the fear system in action. They illustrate the fear responses humans share with other animals, particularly the biological mechanisms that reset the fear system after a major threat.

I am using the term ‘fear system’ to cover three responses to danger or threat. The first (not illustrated in the videos) is fear alert, which is our response to danger sensed at a distance. We go very still, hold our breath, and try to locate the threat; meanwhile, our startle response is readied.

The second, once the danger is clearly perceived, is fear arousal; the sympathetic nervous system triggers a powerful, sudden physical mobilisation to escape the danger. The third response, when the danger is too close to escape, is fear collapse; the parasympathetic nervous system triggers this shutdown. It also switches a predator’s attack and opens the possibility of a last-ditch escape—and a less fearful, painful death.

Switching from Fear Collapse to Fight-or-Flight

In the first example (click here, but I recommend turning off the sound [1]), we see an antelope in fear arousal (fight-or-flight), being chased by a cheetah, then in fear collapse, caught with its throat in the cheetah’s jaws. The cheetah, exhausted by the pursuit, is then chased off by a hyena. The hyena is about to rip into the antelope’s stomach but is distracted by the cheetah and chases it off again. However, this ‘window of opportunity’ prompts a sudden shift in the antelope from fear collapse to fear arousal, and it makes off at high speed. With both cheetah and hyena nearby, this is not a safe place, but the escape burns off the energy of the fight-or-flight response, and once in a safe place, the antelope’s fear system will reset, ready for the next threat, without any ongoing trauma.

Recovering from Fear Collapse in a place of safety

In the second example (click here), a leopard has already caught an antelope, which is in fear-collapse and lying as if lifeless, eyes open, with its nose in the leopard’s jaws. A hyena is spotted, and the leopard is distracted – notice how, when the leopard releases its grip to look at the hyena, the antelope’s head flops onto the ground. In the metabolic shutdown of fear collapse, the muscles lose their 'tone' or tension – hence the flop.

The leopard is then further distracted by a couple of baboons, which chase it off. The antelope is left lying in the fear-collapsed state, completely still at first. After a few moments, its abdomen moves, it starts breathing deeply, and you see eyelids flicker. Eventually, as it starts to right itself, it shudders for almost a full minute, moving into gentle tremoring; this is the fear system ‘resetting’. Finally, the antelope is up and away.

The Fear-System Reset in Psychotherapy

It is helpful to understand these two natural mechanisms which reset the fear system, as the deactivation of fear responses which have become ‘stuck’ after traumatic experiences is a key task of psychotherapy.

The first video shows a window of opportunity for escape opening in an unsafe setting, with a sudden switch from fear collapse and back into fight-or-flight. Therapists use this pathway out of collapse, switching back into fight-or-flight, to help clients connect with and express anger or aggressive impulses in a safe context (here is an example in my post on retaliatory responses).

The second video shows a recovery from fear collapse in what is now a safe place (protected by baboons). The recovery starts with deep spontaneous breaths that expand the abdomen, followed by a period of shaking or trembling in which the tension and energy of the fight-or-flight impulse dissipate, and the fear system is ‘reset’.

In humans, we see the trembling or tremoring response in the immediate aftermath of a traumatic event, for example, a car accident, when a victim receives good roadside care and starts to feel safe again. Psychologist and medical biophysicist Peter Levine warns against misinterpreting trembling and treating it with medical intervention, which can interrupt the recovery [2].

Certain practices aim to replicate this natural trauma-recovery mechanism and are widely used to help emergency first responders process secondary trauma from their work [3, 4].

Less commonly, we observe tremoring in the therapy room, though it can manifest subtly, such as gentle trembling or a flush of heat that may not be noticed or understood [5]. In my own practice, I was made aware of it by clients who reported trembling when safe in bed at night after experiencing a breakthrough in their therapy session.

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