Mesocricetus Auratus Preference for Substrate Quantity vs Enriched Commercial Housing Options: A Case Report

M. auratus is a common companion and laboratory animal in many countries around the world. Many guidelines recommend housing M. auratus in enriched enclosures that are as large as possible with a bedding depth of approximately 2.5 cm. However, given that wild M. auratus will build intricate burrows it is uncertain whether M.auratus would actually prefer to nest in an enclosure that provides enrichment relative to an enclosure that provides a greater substrate depth to facilitate natural behaviours. We provided a female M.auratus with an 8 m2 pen containing a 30L tub containing recycled paper bedding, an enriched 3-storey commercially available cage that included a running wheel and 2.5 cm of bedding in the bottom, and enrichment derived from a mixture of commercial products and recycled household products (RHPs; e.g. cardboard boxes). When randomly sampling the location of M. auratus during a 3-month study period, we found that virtually all nesting behaviour, including hoarding, sleeping, and burrow construction occurred within the tub. While approximately 31% of non-nesting behaviour centred around the cage, no nesting behaviour occurred there. Moreover, of the interactions with external enrichment in the pen, we found that over 90% of interactions were with RHPs rather than commercial products. We conclude that M. auratus is likely to prefer housing conditions that provide greater quantities of substrate in which they can emit their natural burrowing behaviours, that they value burrowing and nesting opportunities to a greater extent than even multi-level above-ground enriched areas, and those simple cardboard boxes may provide better enrichment than expensive commercial products.