EN
Stereotypic behavior is treated as an essential indicator of animals’ welfare. The occurrence of this behavior stems from the dissonance between the conditions in which they are kept and those preferred by the animals and fulfilling their biological needs. The contemporary studies concerning this behavior involve both definitions and classifications of basic concepts associated with these types of disorders. The majority of those definitions characterizes stereotypic behaviors as being invariant, repetitive and with no obvious goal or function. The criteria are often equivocal or their meaning imprecise. The variety of forms and types of this behavior indicates that different types of stereotypes are the result of different disturbances in interactions between an animal and its environment. Difficulties to classify the types of stereotypical behaviors are the result of the equivocality of the criteria, thus one form can often be classified to many types. Some among the few classifications focus more on the frequency and intensity of symptoms, others on causes. Here we present a review of various definitions with the criteria being used to describe this abnormal behavior.