Age-Related Changes in the Body Size and Weight of Sika Deer (Cervus nippon): A Comparison between Northern and Southern Populations of Honshu, The Main Island of Japan

The sika deer (Cervus nippon) is known to exhibit north-south variations in body size, but growth patterns and sexual size differences are not well studied. This study compared age-related changes in the hindfoot length and body weight of deer in the northern and southern populations in Japan. Hindfoot lengths of the northern deer were 12% (males) and 9% (females) longer and the body weights were 19% (males) and 8% (females) heavier than the southern deer. Hindfoot length increased from fawns to two years of age and then remained stable in both sexes in the northern deer, while it increased to yearlings in both sexes in the southern deer. Male body weight significantly increased until three years in the northern deer and until two years in the southern deer. Female body weight significantly increased until two years both in the northern and southern deer. Male/female ratios were greater in the northern deer than in the southern deer. We showed that 1) the northern deer were larger, 2) males were larger than females in both places, 3) males grew faster for a longer period than females, and 4) sexual dimorphism was more pronounced in the northern population. Received 9 November 2023. Accepted 22 April 2024.