Species specific differences in short-term behavioral reaction of voles to cage elements removal

Abstract

The welfare of animals used in scientific experiments should be one of the most important things to take care of. Many kinds of research show that the enriching elements can help animals to fulfil their natural behaviour. However, those studies have been performed on the most popular laboratory animals, which include mice and rats. The rules developed on the base of such studies are implemented to all animals used in experiments, even wild ones. The experiment we’ve conducted investigated the short-term behavioural response of non-laboratory rodent species to eliminating enriching elements in their cages. Two closely related species: bank voles (Myodes glareolus) and common voles (Microtus arvalis) were used in the experiment. Both species differ in their social characteristics; bank vole is a territorial species whereas common vole is a social one. Moreover, other studies showed the differences in the behavioral response to new environmental enriching elements between the two species. The studied animals were kept in the cages individually or in groups of three. Their behaviour was recorded for two 30-minutes phases - the first one with enriching elements (bricks and tunnels) and the second, after the elimination of the objects in the experimental group. Recorded behaviour was assigned to different categories such as "stereotypic" "eating and drinking", “other behaviour" and „non-activity". The time spent on stereotypic behavior and non-activity was significantly influenced by the number of animals reared together and the reaction differed between species. While the presence of other individuals had a significant effect on the overall score of stereotypic behavior in common voles, it did not have the same effect in bank voles. The removal of the enriching items had also a different effect on the behavior of both species. Bank voles spent more time on non-activity after item removal compared to control group. In contrast, common voles did not exhibit more stereotypies after removing the items. Additional items in cages are essential for laboratory species to enrich their environment and meet species’ specific requirements. However, our studies have shown, that even if the species are closely related, their surrounding preferences and behavioural reaction to removing the items can be different. We suggest that due to those differences, meeting the specific needs of a particular species is crucial to make sure the animals have the best possible conditions in the laboratory, the conditions that mimic their natural habitat and requirements to the highest extent.