Sika deer (Cervus nippon) was one of the major terrestrial mammals hunted in Japan throughout the Jomon period, which extends from the end of the Palaeolithic until the arrival of rice agriculture in the first millennium BC. Mandibular analysis of hunted deer is believed to be more useful in determining the season of death than antlers in archaeological contexts. This paper aims to present a new method of estimating an occupational season of a Jomon site by using sika deer mandibles. This method consists of two stages. First, two measurements on a mandible should be taken. If the distribution shows any gaps among young juveniles, this strongly suggests that the sika was hunted in a specific season. Second, tooth eruption and attrition stage should be observed; this may suggest the season in which hunting took place. This method was utilized to analyse sika deer remains from Awashimadai in eastern Kanto. The result of the analysis shows that deer were hunted only from spring to summer at Awashimadai. Putting these results together with the estimate of seasonality deduced from other species strongly suggests that the site was occupied only from April to July.
This paper also examines how the tooth attrition stages of sika deer progress. The preliminary comparison with red deer (Cervus elaphus) in England suggests that molar wear progresses more quickly in sika than in red deer.