Seasonal Changes in the Diet of Urban Raccoon Dogs in Saitama, Eastern Japan

Abstract

We examined the food habits of raccoon dogs (Nyctereutes procyonoides) at an urban high school in Saitama, Japan. The study place is surrounded by residential areas but is adjacent to a pond. Fecal samples (n = 126) were collected from January to December 2022 and analyzed using the point frame method. Fecal composition was diverse in winter, including leaves, fruits, seeds, and artificial materials. In spring, the proportion of Japanese toads (Bufo japonicus formosus) and insects increased, whereas in summer, proportion of hackberry (Celtis sinensis) fruits, insects, and red swamp crayfish (Procambarus clarkii) increased. In autumn, fruits of hackberry and muku tree (Aphananthe aspera) were predominant. Consumption of toads and swamp crayfish suggests that the raccoon dogs are opportunistic feeders. We recovered seeds from only ten species, including fruits from five wild plants; these numbers were lower than those reported previously in rural areas of the same district, where raspberries (Rubus spp.), mulberries (Morus spp.), and Eurya japonica have often been recovered at great proportions. A wide range of artificial materials were recovered but in low quantities. These results reflect the characteristics of the study area, which is an urbanized environment with limited trees and adjacent to a pond.