Abstract:

Environmental temperature has a significant impact on human body size and its proportions, which is often referred to as Allen’s rule, that warm-regional species tend to display shorter appendages (limbs, ears and tails) than cold-region ones. But recent studies have paid less attention to this Allen’s rule in physical anthropology. Thus, this paper studies the relationships between absolute and relative limb size and temperature among different regional populations to test whether Allen’s rule exists in modern Chinese populations. We collected 17 measurements of the upper and lower limbs in modern Chinese populations from 102 sites, and took mean annual temperature (MAT), annual highest temperature, annual lowest temperature and annual range of temperature as the temperature indices.
As the environmental temperature decrease, the upper limb tends to become shorter and robust, and the lower limbs become longer. The results also showed a positive correlation of most limb measurements and MAT, whereas the stature-upper limb length index is negatively correlated with MAT. Based on the above results, we suggest the temperature can be taken as an environmental selection pressure that play more important roles in shaping the upper limbs than that of the lower limbs. Moreover, the variation of limb morphology in modern Chinese populations is not completely in accordance with Allen’s rule, which may be associated with the development of body proportions under the combined effect of influential factors including genetic background, geographical climate conditions, functional requirements (biped or dexterous manipulation), survival strategy and nutrition.

Key words: Allen’s rule, Modern Chinese populations, Temperature, Limbs, Environmental adaptation