AbstractDifferences in exploratory behaviour measured by apparatuses with different properties were investigated in 98 litters of control mice in two-generation toxicity studies over a 13-year period. The exploratory behaviour of F-generation mice was investigated at 3 weeks of age during the lactation period and at 8 weeks of age after weaning. Exploratory behaviour was measured by two animal movement analysis systems: ANIMATE AT-420 (62 litters) and SCANET CV-40 (36 litters). Three-weeks-old male and female offspring in the SCANET group showed lower activity than the ANIMATE group for all variables, excluding the number of horizontal activities, which increased more in the SCANET group than in the ANIMATE group. Furthermore, 8-weeks-old male and female mice in the SCANET group showed lower activity than the ANIMATE group for all variables, excluding the number of horizontal activities, rearing time, average rearing time and number of defecations. The number of horizontal activities increased in both sexes in the SCANET group. The rearing time was similar in males in two groups and was significantly longer in females in the SCANET group. The average rearing time was significantly longer and the number of defecations significantly increased in the SCANET group. In this study, the differences in the properties of the two measuring apparatuses were the luminosity in the field and the shape of the cage, and these variables affected the measurements. Thus, the differences in
the measuring apparatuses need to be considered when comparing the different test results for exploratory behaviour.