Eruption of posterior teeth in the maxilla and mandible for age determination of water deer

Objective Eruption of posterior teeth, including premolars and molars in the mandible rather than in the maxilla, is accepted as an accurate reference for age determination of deer. In water deer, Hydropotes inermis, the eruption age of mandibular molars has been described in two studies, but the ages were inconsistent with each other. In this study, we aimed to confirm the eruption age of mandibular posterior teeth for the accurate age determination of water deer and to evaluate the efficacy of maxillary posterior teeth for the age determination of deer. Design The eruption of mandibular and maxillary posterior teeth was investigated in the dry skulls of individual wild water deer of both sexes, up to an age of about 15 months. Results The eruption age of mandibular molars in water deer was consistent with that of a previous study. The eruption age of posterior teeth was almost the same in the maxilla and mandible of individual water deer. The deciduous mandibular fourth premolar and the permanent maxillary fourth premolar were two easiest teeth to be identified for the age determination. Conclusions The former controversial eruption age of mandibular posterior teeth in water deer was confirmed. Our study first presented the eruption age of maxillary posterior teeth in water deer. It is suggested that posterior teeth not only in the mandible but also in the maxilla are useful indicators for the age determination of water deer.