The present study focused on the above-ground activity of shrews by observing their climbing frequency and duration on aerial parts of plants in a laboratory setting for four sympatric shrew species (Sorex unguiculatus, S. caecutiens, S. gracillimus, and S. minutissimus) in Hokkaido, Japan. All shrew species utilized aerial parts of plant. The lighter S. gracillimus tended to exhibit a higher frequency and longer duration of climbing on aerial parts compared to the heaviest S. unguiculatus, which tended to avoid using such parts. While the sample size is small, the smallest S. minutissimus and medium-sized S. caecutiens seemed to use more aerial parts than S. unguiculatus. All shrew species tended to prefer using the fuki butterbur and the sasa bamboo compared to the other plant types. Additionally, S. unguiculatus and S. caecutiens tended to avoid the use of herbs with the thinnest diameters. These findings are probably related with the diameter and morphology of plant. The result of the present study provides novel insights into the potential niche separation among the four sympatric shrew species in Hokkaido.

Published online 13 March, 2024; Print publication 30 April, 2024