Effects of climate factors on the activity of a viperid snake, habu (Trimeresurus flavoviridis) : based on the frequencies of bite cases of sleeping men in the Okinawa Islands.

Abstract

The activity of a venomous snake, habu (Trimeresurus flavoviridis) was represented by the frequencies of bites of sleeping men in the Okinawa Islands. Five climate factors recorded at the Okinawa Meteorological Observatory were selected to get correlations to the snake activity on each day in each season through logistic regression analyses. Habu was estimated to be active on the days of low means of air pressure in winter, of high means of air temperature in March, or high means of humidity in autumn. In summer with high means of air temperature and humidity few climate factors were correlated to the snake activity. The patterns of seasonal change in mean temperature and mean humidity corresponded with these results. The mean air temperature, the mean humidity and the precipitation were the first, second and third important factors, respectively, in the analyses of all through the year. This is the first intensive study to analyze the daily change in the snake activity in field.