Abstract
The activity of the himehabu increased notably twice per day, at 6-10 P. M. and at 5-9 A. M. It is evident that the himehabu possesses a rhythm of activity with periods about half a day in length. These times when the himehabu became active were suddenly rising periods of humidity. If the humidity rises suddenly in the day-time because of a rainfall, the himehabu becomes active.
Therefore, the sudden rise of humidity is thought to be the trigger that induces a half-day rhythm of activity at ordinary times. The time of occurrence of human himehabu bite cases was independent of snake activity.
