Abstract:
During the pre-reproductive period, the nocturnal active rhythm of the Chinese giant salamander Andrias davidianus and environmental factors were investigated from July to August in 2011 at imitated-natural habitat of the Qinling Mountains using all occurrence recording methods. The results showed that Chinese giant salamander moved out at 7:30 PM, their activities reached the peak in 9:30 PM and remained to the next day 1:30 AM. After 6:30 AM, all Chinese giant salamanders returned to the den. There were significant differences in nocturnal activity between male and female, while there were no difference in nocturnal activity between the adult and the subadult. Illumination intensity and water temperature were well correlated with the nocturnal activity times. The Chinese giant salamander began to come out or to back when the illumination was 685～1 431 lx or the relative illumination was 3%. The peaks of activities occurred when the water temperature ranged from 17.1～18.4℃ (2 hours after the illumination was 0 lx). This study demonstrated that the illumination and water temperature affected the nocturnal activity rhythm of the Chinese giant salamander during the pre-reproductive period, the illumination was the key factor which controlled the activities outside of the den, and the water temperature was the main factor to determine the activity peaks.
