A scheme developed by Brown & Chapman, (1991a), which allocates scores to stages of tooth development from radiographs, has been applied to 12 of the 28 roe deer (Capreolus capreolus) mandibular rami recovered from the early Mesolithic site of Star Carr, N. Yorkshire (c. 7500 BC). The mandibles of 35 known-age roe deer kids from Britain and Denmark were also radiographed. The developmental stages of all premolars and molars were analysed and assigned a score using the scheme. After radiographing, four of the Star Carr rami could be paired with a fair degree of confidence, reducing the sample size from 12 to 10 roe deer. Comparisons of scores between the archaeological and modem populations revealed that seven of the Star Carr mandibular rami are aged approximately 10 to 11 months. The youngest is nine months, and the oldest 12 months. These results have significant implications for determining the seasonal presence of humans at the site. Contrary to the received view of a purely late spring/summer occupation of the site, it is now apparent that Star Carr was also visited during the late winter and early spring.