The structure and exploitation of Citellus dauricus caves in Hailar East Mountain

From May to October in 2011, the caves of twelve non-breeding Citellus dauricus were dug and measured in Hailar East Mountain in Hulunbuir city of Inner Mongolia. The results were as follows: the caves of Citellus dauricus were classified into two categories, namely temporary holes (summer holes) and live holes (hibernation holes). The entrance direction of the caves was towards the northwest or northeast. Temporary hole in structure was simple and majority of temporary holes only had one entrance, while hibernation hole in structure was more complex and the entrance of hibernation holes was smooth. The mean width of the entrances of hibernation holes was usually from 6 to 9 cm. The tunnels near the cave entrance slanted to the below, and turned sharply downward, almost vertical, and then slanted a distance till into the nest. The mean depth was from 90 to 100 cm. The overall length of a cave was approximately from 110 to 126 cm. Bifurcation of the caves was less and the nest shape of the middle tunnel was flat. The nests were padded with crushed grass, plastic and foam, and the toilets were near the nests. Most of the caves of Citellus dauricus had a blind hole, which located away from cave entrance at 30 to 60 cm.