The Hour Between Dog and Wolf: How Risk Taking Transforms Us, Body and Mind

by John Coates

In reptiles, the vagus orchestrates a primitive reaction to threat—freezing into a motionless state. Reptiles freeze in order to conserve their limited energy and avoid detection. This freeze response was subsequently passed on to mammals, in which it proved useful as a way of feigning death when a threat loomed. Something like the freeze response is also activated in mammals living or feeding in water, such as seals, in order to slow heart rate and metabolism and conserve oxygen when diving to great depths. The vagal freezing response lingers to this day in most mammals, and can show up under circumstances of extreme danger. When escape from a predator is deemed impossible, a mammal can call on this ancient reaction, and its physiological systems will more or less shut down. Movement ceases, breathing slows, heart rate drops, sensitivity to pain decreases—pathetically, the animal may provoke cardiac arrest and die from its own reaction to threat rather than from the predator itself. Something like this phenomenon has been observed in wild rodents trapped in water they fear they cannot escape. These poor animals, realizing the futility of struggle, frequently opt for freezing and cardiac arrest, some of them even diving into the depths, drowning themselves. Presumably they do so to trigger a dive-induced freezing, leading to a rapid and painless death.