Many species of frogs coexist in urban areas of Japan, though there have been few studies on the manner of their coexistence as well as the competition and/or segregation on their food resources.

Surveys of the diets of four species of frogs (Rana brevipoda, R. escullenta, R. rugosa and Fejervarya limnocharis) were performed in the paddy area in Otsu, Japan, three times from August to October 2010, Sampled frogs were released to the original habitat after recording their stomach contents, wet weight of stomach contents, snout-vent lengths and wet weight. From 581 individuals of frogs, 5220 items of gastric contents were detected.

Analyzing the diet pattern of the fullness of stomach contents of frogs, the species segregated the foraging time but predated upon the similar food animals in August. In September and October, they showed only a few segregation by time, though taking different food items. Details will be present by analyzing the similarities and overlaps using weight ratio of stomach contents.