Behavioural correlates of stereotypic behaviour in Rhabdomys dilectus
Date
2018
Authors
Silber, Sarah
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Abstract
The specific causal mechanisms of stereotypies are difficult to establish, especially
because they do not develop in all individuals of a species living in the same captive
environment, and may be affected by other behaviours (e.g. personality) and the life
history of the animal. The overarching aim of this study was to investigate the
behavioural correlates of stereotypic behaviour in the striped mouse Rhabdomys dilectus,
and to ascertain whether there are any specific traits associated with stereotypic
behaviour in this species. I studied the behaviour of stereotypic and non-stereotypic
striped mice in four behavioural assays, including: (1) general home cage behaviour; (2)
dyadic encounters to assess social interactions; (3) personality tests to measure interindividual
variation in behaviours; and (4) perseveration tests by means of a plus maze.
Results indicated that: (1) stereotypic striped mice showed higher frequency and duration
of active behaviour and higher rates of inactivity, whereas non-stereotypic mice displayed
longer durations, but fewer occurrences, of inactivity; (2) social motivation was not a
predictor of stereotypic behaviour in striped mice; (3) Stereotypic mice showed a
proactive coping style typified by spending a longer time in the light compartment after a
startle response, a greater manipulation of novel objects in the home cage, and increased
activity levels in standard housing. Non-stereotypic mice showed a reactive coping style
typified by greater anxiety and fear toward novel objects, and heightened inactivity; and
(4) levels of perseveration were higher in stereotypic striped mice. I also found that
stereotypic mice that showed higher frequencies and durations of activity also displayed a
proactive coping style and were more preservative. In addition, non-stereotypic mice that
were inactive for longer showed a reactive coping style and lower levels of perseveration,
which suggests inactivity is a possible alternative response to stereotypy in captive
environments. In conclusion, stereotypy, activity, personality, and coping style appear to
have common underlying, possibly neurobiological, mechanisms. In particular, I
hypothesise that dysfunction of the basal ganglia, or suppression of the indirect
(striatopallidal) pathway, results in inappropriate repetitive responses and stereotypic
behaviour. Further research is needed to measure brain hormones and structure in order to
determine the nature of the imbalances and whether they are consistent within and
between species. In addition, investigations are required of factors which may mediate
these imbalances, including age of weaning and other genetic influences.
Description
A dissertation submitted to the Faculty of Science, University of the
Witwatersrand, Johannesburg, in fulfilment of the requirements for the
degree of Master of Science.
Johannesburg, 2018.
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Citation
Silber, Sarah, (2018) Behavioural correlates of stereotypic behaviour in Rhabdomys dilectus, University of the Witwatersrand, Johannesburg, https://hdl.handle.net/10539/25628.