Annual and daily activity patterns of Dipsas bucephala from southeastern Brazil were characterized respectively from the Instituto Butantan (São Paulo, Brazil) collection data over a 21-year period and from individuals video-monitored in laboratory continuously. D. bucephala was more frequently collected in summer (second half of the rainy and warm season) with a peak in March, which indicates a seasonal and unimodal activity pattern. Temperature and precipitation seems to explain only a part of this variation. Prey availability throughout the year and reproductive events are other factors likely to shape this pattern. Higher activity in the summer would be synchronic to a higher mollusk abundance. Gravid females were found only during spring. Thus, the peak of activity in late summer may be related to an increase in male activity due to mate search. Daily activity occurred during the nocturnal period (between 17:30 and 06:00 h). Peaks were unimodal, registered between 19:00 and 02:00 h, and were longer than those observed in other snakes. This extensive activity period may be related to an intensive foraging activity in malacophagous snakes. Moreover, peaks of daily activity were higher when food was available. The lack of chemical stimulus (mucus trail) may explain the lower peak of activity in experiments without food.