To reveal latrine use patterns in low density Japanese badgers, a novel “Trace Recorder” system was developed to track three individuals (two males and a female) between two groups in Hinode-town, a suburb of Tokyo in 1997. A young adult male was observed to intrude into the ranges of neighbouring adult females during the mating season and to make frequent visits to hinter and border latrines within their natal ranges. Findings suggest that extra-group mating may be facilitated by the border latrine communication where scent marking can be effective information sources of badger presence and oestrous status.