The lower-row cage may be dark, but behavior does not appear to be affected (2000)

Schapiro, S. J., Stavisky, R., Hook, M.

Abstract

The situation of 3 upper-row single-caged females was compared with that of 6 lower-row single-caged females. Mean light levels at nine different positions within the cage were significantly lower in bottom-row cages than in upper-row cages. Not only did light levels differ significantly, but less than 8% of light readings in lower-row cages were higher than the lowest light level readings at the same position in the upper-row cages. .... There were no statistically significant differences in behavior [abnormal, inactivity, grooming, drinking, feeding, exploring, lip smacking]. The mean percent time spent in abnormal behavior was 0.7 for upper-row caged subjects versus 1.6 for lower-row caged subjects.