[Studies on hibernation pivotal temperature of Whitmania pigra].

The biological characteristics, oxygen consumption, oxygen consumption rate, and activities of amylase, lipase and protease of Whitmania pigra at different temperature were studied by using direct observational method, the still water method and 3, 5-dinitrosalicylic acid colorimetry, right-nitrophenyl palmitate ester（ρ-NPP）colorimetry and folin-phenol method.The results revealed that with decreasing water temperature, the daily activity and the daily feeding ration were decreased. As the temperature was lowered to 4 ℃, the head and tail of Wh.pigra curved, showing a crescent-shape without feeding and daily activity. Oxygen consumption, oxygen consumption rate and digestive enzyme activities reduced along with temperature drops. The downward trend slowed below 10 ℃, began to stabilize below 4 ℃ and doesn't change with the decrease of temperature since then. During the 40 days treatment at 4 ℃, the changes of amylase were not significant, the lipase and protease activity decreased at the 20th day, and the lipase showed an slightly increase after the decrease and finally remained at a low level.In conclusions, the pivotal temperature of hibernation of Wh.pigra is 4 ℃ and the crescent shape can be considered as a symbol of hibernation.