Stereotypy (non-human)

In animal behavior, stereotypy, stereotypical or stereotyped behavior has several meanings, leading to ambiguity in the scientific literature. A stereotypy is a term for a group of phenotypic behaviours that are repetitive, morphologically identical and which possess no obvious goal or function. These behaviours have been defined as ‘abnormal’ as they exhibit themselves solely to animals subjected to barren environments, scheduled or restricted feedings, social deprivation and other cases of frustration, but do not arise in ‘normal’ animals in their natural environments. These behaviors may be maladaptive, involving self-injury or reduced reproductive success, and in laboratory animals can confound behavioral research.

Stereotyped behavior can also refer to normal behaviors that show low variation. For example, mammalian chewing cycles or fish capturing prey using suction feeding. Highly stereotyped movements may be due to mechanical constraint (such as the skull of a viper or fish, in which bones are mechanically linked), tight neural control (as in mammalian chewing), or both. The degree of stereotyping may vary markedly between closely related species engaging in the same behavior.

The display of stereotypies is usually increased in an individual over time, this is due to the changing motivation of the stereotypy. The establishment of the stereotype may be due to a number of factors within a captive environment, however the continuance of the behaviour can be explained by its impact on the basal ganglia and the establishment of a habit in its expression. The interruption or cease of a habit is much more tedious and difficult than that of the initial behaviour. Secondly, as stereotypes develop, they become more readily elicited, so much so that they are no longer just expressed during the original circumstances and may be expressed in the absence of any apparent stress or conflict. The development of the stereotypy into a habit and the difficulty of interrupting said habit explain why it is expected that the frequency of stereotypies increases with age.

It is assumed that the onset of the development of stereotypies is due to poor coping with the animal's environment, and is considered one of the most important indicators of long-term animal welfare problems, a prolonged display of stereotypies suggests that the welfare of the animal is in a peril state. The welfare of the mink is considered an important aspect from a management stand point as it has repercussions on the production of the animal. Inadequate welfare has been linked to poor reproductively, poor growth rate.

Many stereotypies can be induced by confinement; for example, cats pace in zoo cages. Pregnant sows whose feed is restricted bite at their stalls' bars and chew without anything in their mouths. In laboratory rats and mice, grooming is the most common activity other than sleep, and grooming stereotypies have been used to investigate several animal models of anxiety and depression.

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