The locomotor activity patterns of two species of shrew were investigated under both standard laboratory conditions and in their natural environment. Trapping, using live traps, was undertaken on a seasonal basis to determine the predominant periods of activity for each species in their natural habitat. We assessed if there was a seasonal variation to the locomotor activity in the shrews. In the laboratory, locomotor activity patterns were investigated under the following lighting conditions, in sequence; 12L:12D (2 weeks), constant darkness (3 weeks), 12L:12D (2 weeks), 12D:12L an inverted light cycle (2 weeks) followed by 6 weeks at 16L:8D and 8L:16D for each species. Temperature was maintained at a constant temperature of 25 ± 1°C. Foraging behaviour and body mass changes were recorded throughout the study. Both species exhibited predominantly nocturnal locomotory activity patterns under laboratory conditions. In the field the forest shrew, Myosorex varius, altered its predominant activity period depending on the season, displayed polyphasic activity patterns and was caught throughout the year; it neither gained nor lost body mass. The greater red musk shrew, Crocidura flavescens, was strictly nocturnal in the field, more so than under laboratory conditions, gained body mass readily in the laboratory and was very rarely captured during winter. Therefore, each species displayed slightly different behavioural adaptations when exposed to the same conditions. These findings emphasize the similarities and differences in activity amongst co‐occurring small mammal species in light of possible competition avoidance mechanisms.