Use of PVC conduits by rats of various strains and ages housed singly and in pairs (2000)

Galef, Jr. B. G., Sorge, R. E.

Abstract

Adult male Long-Evans rats rarely entered PVC conduits unless housed in pairs. ... Adult male Sprague-Dawley rats entered PVC conduits only during the illuminated portion of the day-night cycle and only if housed on shelves exposed to direct overhead illumination. Both juvenile rats and female rats made extensive use of PVC conduits throughout the day-night cycle.The authors provisioned the single cages [500 cm2] of male Sprague-Dawley rats [n=12] with PVC tubing with a length of 14.8 cm and a diamter of 7.5 cm. The animals were never observed inside the tubes during the night. They used the tubes during the day signficantly more often [about 60% of observations] when their cages were located on the top shelf than when their cages were located on the bottom shelf [about 8% of observations]. It stands to reason to infer that the rats used the tubes as protection against overhead light exposure which was significnatly more intensive on the top shelf than on the bottom shelf.