'Anxiety' in laboratory rodents: a brief review of some recent behavioural developments

It is clearly difficult to determine which of the multitude of behavioural and physiological indices provides the most reliable indicator of 'stress' in any particular animal. Although 'fear' and 'anxiety' have obvious survival value in feral animals, the induction of intense or chronic states of fearfulness are likely to account for much of the 'stress' which concerns applied ethologists, animal welfare students and keepers of animal collections etc. Recent developments applying ethoexperimental approaches (combining ethology and experimental psychology) to the study of behavioural indicators of anxiety in rodents, seemingly provide useful indicators of 'stress'. The areas looked at are predator-prey interactions, studies on ultrasonic 'distress calls' in neonates and analyses of fearful defensive behaviour in dyadic encounters.