The dioecious snail Cerithidea rhizophorarum is found throughout the coasts of West Pacific up to the Tohoku district northward in Japan. It inhabits reed grassland and mangrove forest on mud flats. In Kagoshima prefecture, this species are commonly found in a mangrove forest with Kandelia candel and Hibiscus hamabo trees on a mud flat located at the mouth of Atago gawa river in Kiire. Interesting behaviors including mating and tree climbing behaviors of this species were studied there, for approximately two years from April 2000 to May 2003 on this mud flat.
Mating behavior was observed in July and August 2002. The time of commencement and termination, and duration were recorded for each copulation. The peak of matings during daytime was seen 1 to 2.5 hours before the lowest tide, and that during nighttime between 1 hour before and after the lowest tide. However, the mating almost did not occur on cloudy days.
Climbing behavior was observed in an area of 100 square meters where only Kandelia candel trees existed. The number of snails on the tree was counted and daily activity of the snails on trees was monitored in summer and winter, counting the number of the snails on the tree every one hour throughout the day. The snails were mainly found on the mud from spring to summer, frequently climbed up the tree in particular time zones during summer, and most individuals were seen on trees and motionless during winter.