Abstract:

Sexual size dimorphism is the commonest form of sexual dimorphism, associated with growth patterns, mortality and food availability, which has become a hot topic of common concern in recent biological anthropology. In all living human populations, males usually show a larger body size than females. Over the last 40 years, many scholars have reported numerous anthropometric data sources on stature for modern Chinese, but little attention has been directed to the sexual dimorphism variability. In addition, what factors governing the inter-populations variation in SSD are still not clearly understood. The present study aimed to describe the variability in sexual stature dimorphism for modern human populations in China, and reassessed whether the geo-climatic factors and body size are associated with variation in sexual starure dimorphism. Data on sex-specific anthropometry (mean stature) was obtained from 152 modern Chinese populations, including 69 Han and 83 minority nationalities. The sexual dimorphism index was compared to assess difference in four groups (Southern Han, Northern Han, Southern Minority and Northern Minority). The latitude, climatic variables, body size and urban-rural environment were tested for their association with the sexual dimorphism. The results showed that males are about 7.16% (ranged 4.72%~9.26%) taller than females. The distribution of SDI are resemble between the Southern Han and Southern minority, the Northern Han and Northern minority, the Southern Han and Northern Han. Moreover the Southern minority displayed lower sexual dimorphism compared with the Northern minority. The latitude, annual temperature range and annual average wind speed are positively associated with sexual starure dimorphism, while the annual average temperature, annual average precipitation and annual average relative humidity are negatively associated with sexual starure dimorphism. In addition, this study found no significant allometric relationship between male and female stature agreed with the Rensch’s rule, may be related to the sexual selection perference favours other social compents rather than stature. It also reveals no significant difference in sexual stature dimorphism between urban and rural Han populations, inconsistent with female buffering hypothesis, reflecting poor diet and hard physical labor have less negative impact on the boys’ physical growth. Genetic component and natural environmental factors are the dominant determinant of the regionalization distribution in sexual stature dimorphism, while the social environmental factors do not exert a strong influence in the degree of sexual dimorphism. Although the samples are limited by individuals of different ages, it still helps us to insight the geographical distribution of sexual stature dimorphism in modern Chinese.

Key words: Homo sapiens sapiens, Chinese, stature, sexual dimorphism, environment