Byrd, C. P., Winnicker, C., Gaskill, B. N. 2016. Instituting dark-colored cover to improve central space use within guinea pig enclosure. Journal of Applied Animal Welfare Science 19(4), 408-413.

Domestic guinea pigs (Cavia aperea f. porcellus) in laboratories have been shown to actively avoid the centers of their cages. This experiment tested a novel, dark-colored “shader” placed over the central portion of a cage. Based on the observed behavior of wild guinea pig species, it was hypothesized that utilization of the central portion of the cage would increase when the shader was present. Eleven male and 11 female albino, 3-week-old Hartley guinea pigs (Crl:HA) experienced the control and treatment conditions in a crossover study design. They spent more time in central cage sections when the shader was present and spent more time in and around the food hopper when the shader was absent (p , .001). Differences between sexes included increased inactivity in males versus females (p , .05) and a difference in time spent in a corner section of the cage (p , .001), likely associated with location in the room. We concluded that the presence of a shader increased utilization of cage space, which appeared to provide a similar increase in space utilization as structural enrichments.