Refuge cover decreases the incidence of bite wounds in laboratory South African clawed frogs (Xenopus laevis)

The Guide for the Care and Use of Laboratory Animals recommends environmental enrichment for all laboratory animals, including amphibians. In this study, we evaluated the effect of adding environmental enrichment in the form of acrylonitrile-butadiene-styrene (ABS) pipes as covered refuge for laboratory Xenopus laevis housed in 2 pond-style tanks (capacity, 300 1; stocking density, approximately 150 frogs/tank; dimensions, 1.3 x 1.8 x 1.3 m). Medical records from animals housed in these 2 ponds between 1 January 2001 to 31 December 2003 revealed the incidence of bite wounds to be 5.0%, 4.0%, and 5.0% annually, respectively, and indicated 2 episodes of cannibalism (in 2003). In January 2004, we added ABS pipes as refuge housing to these tanks and continued to monitor the number of bite wounds and cannibalism. Over the following 24 mo (1 January 2004 to 1 January 2006), the incidence of bite wounds declined to 0.3% and 0.7% annually, respectively; no episodes of cannibalism were reported. The results of this investigation indicate that environmental enrichment in the form of ABS pipes for refuge cover has a quantifiable beneficial effect on the physical and social wellbeing of laboratory Xenopus laevis.