Identification of mammal species preyed upon by urban foxes (<i>Vulpes vulpes</i>) in Sapporo, Japan, determined by fecal DNA analysis

Red foxes living in urban areas are called "urban foxes," and their numbers are increasing in Sapporo, northern Japan. Ecological features such as their food habits could have changed compared with foxes in rural areas. To investigate the diet of urban foxes, we developed a method for detecting mammalian prey species by non-invasive fecal DNA analysis. Target-specific PCR primers were designed for possible prey species, including eleven wild mammals and three livestock animals. Fox fecal samples (N=78) collected in Sapporo were surveyed for prey species. We detected the gray red-backed vole (which had been considered the principal prey species), chicken, and pig at high frequencies. The brown rat, a typical urban rodent, was also detected in some fecal samples from central Sapporo. The foxes in Sapporo frequently used foods characteristic of urban areas, including anthropogenic sources such as garbage.