Hypnotised Shark

Tonic immobility has also been hypothesized to occur in humans that are subject to intense trama such as rape or sexual assault.
Tonic immobility as a scientific tool
According to Gilman et al. the investigation of ‘animal hypnosis’ dates back to the year 1646 in a report by Kircher. As a scientific tool, tonic immobility is considered to be a fear-potentiated response induced by physical restraint and characterised by reduced responsiveness to external stimulation. It has been used as a measure in the assessment of animal welfare, particularly hens, since 1970. The rationale for the tonic immobility test is that the experimenter simulates a predator thereby eliciting an anti-predator response - "death feigning". The precept is that the prey animal 'pretends' to be dead to be able to escape when/if the predator relaxes its concentration. Death feigning birds often take advantage of escape opportunities; tonic immobility in quail reduces the probability of the birds being predated by cats.