Abstract
The Kikuzato's brook snake, Opisthotropis kikuzatoi, is a highly endangered aquatic or semiaquatic species endemic to Kumejima Island of the Okinawa Group, Ryukyu Archipelago. Field studies were carried out for some ecological aspects of this species by visiting its habitat almost every month from April 1996 to March 1997. The results demonstrate that the snake is active almost throughout the year. It is also suggested that the snake tends to be diurnal in the warmer season, and nocturnal in the cooler season. Observations on a case of autonomous emergence onto the land, very slow growth, and predation on small crabs, are also provided.
