Abstract
The author investigated the factor of maintenance of the Rana prosa porosa population in the paddy field of the suburban region in southern Kanagawa. Census investigation on a levee to 33% of the target site was conducted 14 times in 2012, and a total of 4,700 individuals were counted. Although the evasion to the levee made from concrete had arisen, the difference between the levee adjoining the concrete waterway and the farm road of the ground was not accepted in adults and yearlings, respectively. From the total extension and standard width of levees, it was guessed that the grassland of approximately 35a existed in the target site. Although it is thin separately, in a large number existing, the levee had become the habitat of this frog species.
