Abstract
The small Japanese flying squirrels, Pteromys momonga, is known to prefer the barks of Japanese cedar, Crytomeria japonica, as a nest material in their natural habitats. In the present study, two experiments were performed to examine the following hypothese: (1) the squirrels prefer cedar bark as a materials because it is easier to strip than the barks of other tree species; and (2) Nests made of cedar bark have better resistance to penetration of water into the core, where the squirrels rest, as compared with nests made of the barks of other tree species. The results denied the hypothesis (1) and supported the hypothesis (2).
