Lapis ISSN 2398-2969


Synonym(s): Trancing, tonic immobility

Contributor(s): Lesa Thompson, Lesa Longley, Anna Meredith


  • Hypnosis or Tonic immobility (TI) is a transitory, involuntary and reversible state of immobility that can be induced by inversion and physical restraint in susceptible animal species.
  • Other terms for this condition are animal hypnosis, immobility reflex, dorsal immobility response, Totstell reflex, death feigning and fright paralysis.  
  • TI has been recognized for over 300 years, with the first study of it reported in chickens in 1636. Since then it has been reported and studied in a wide variety of species, including insects, fish, amphibians, birds, mammals, and possibly in humans.


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Behavioral explanation of TI

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TI in rabbits

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Further Reading


Refereed papers
  • Recent references fromPubMedandVetMedResource.
  • Giannico A T et al (2014)Proven cardiac changes during death-feigning (tonic immobility) in rabbits (Oryctolagus cuniculus). J Comp Physiol A Neuroethol Sens Neural Behav Physiol200(4), 305-310PubMed.
  • Roshchina GIa, Koroleva VI, Davydov VI. (2010)[Changes in the high-frequency electrical brain activity in the animal hypnosis state in rabbits]. Zh Vyssh Nerv Deiat Im I P Pavlova60(3), 352-363 [Article in Russian]PubMed.
  • Rusinova EV, Davydov VI. (2010) Dynamics of changes in electrical activity in the rabbit cerebral cortex during sequential sessions of "animal hypnosis". Neurosci Behav Physiol. 40(5):471-8. 
  • Overeem S, Lammers G J & van Dijk G (2002)Cataplexy: tonic immobility rather than REM-sleep atonia? Sleep Med3, 471-477PubMed.
  • Whishaw I Q, Flannigan K P & Schallert T (1982)An assessment of the state hypothesis of animal hypnosis through an analysis of neocortical and hippocampal EEG in spontaneously immobile and hypnotized rabbits. Electroencephalography Clin Neurophysiol54, 365-374PubMed.
  • Mauk M D, Olson R D, LaHoste G J & Olson J A (1981)Tonic immobility produces hyperalgesia and antagonizes morphine analgesia. Science213, 353-354PubMed.
  • Thompson R K R, Foltin RW, Boylan R J, Sweet A, Graves C A & Lowitz C E (1981)Tonic immobility in Japanese quail can reduce the probability of sustained attacks by cats. Anim Learn & Behav9, 145-149.
  • Carli G, Farabollini F & Lupo Di Prisco C (1979)Plasma corticosterone and its relation to susceptibility to animal hypnosis in rabbits. Neurosci Letters11, 271-274PubMed.
  • Maser J D & Gallup G G (1977)Tonic immobility and related phenomena: a partially annotated, tricentennial bibliography, 1636-1976.  Psychol Rec1, 177-217.
  • Klemm W R (1977)Identity of sensory and motor systems that are critical to the immobility reflex (animal hypnosis).  Psychol Rec1, 177-217PubMed.
  • Carli G (1977)Animal hypnosis in the rabbit.  Psychological Rec1, 123-143.
  • Gallup G G (1977)Tonic immobility: the role of fear and predation.  Psychological Rec1, 41-61.
  • Gallup G G (1974)Animal hypnosis: factual status of a fictional concept. Psychological Bulletin81, 836-853.
  • Klemm W R (1969a)Animal 'hypnosis', an experimental model of EEG-behavioural dissociations. Electroencephalography Clin Neurophysiol26, 336 (Abstract).
  • Klemm W R (1969b)Mechanisms of the immobility reflex ("animal hypnosis") II. EEG and multiple unit correlates in the brainstem. Comm Behav Biol - Part A3, 43-52.
  • Ratner S C (1967)Comparative aspects of hypnosis.In: Handbook of Clinical and Experimental Hypnosis. Ed: Gordon J E. Macmillan: New York, USA. pp 550-587.

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