Age, growth and body size of Bufo minshanicus STEJNEGER, 1926, a toad native to the Tibetan Plateau (Anura: Bufonidae)

According to Bergmann's rule, endothermic species tend to grow larger in cold than warm climates. There are also ectotherms including some amphibian species, that conform to this rule, the validity of which is however disputed as to whether it is generally applicable to all anuran species. Three populations of Bufo minshanicus STEJNEGER, 1926, from along the Huangshui River in the eastern Tibetan Plateau (People's Republic of China) showed that toads from high altitudes were on the average smaller in body size than toads from low altitudes, which is not in agreement with Bergmann's rule. The observations suggest growth-retarding factors to be the major contributor to the smaller body size in the high-altitude populations. The females were significantly larger than males across three sites at different altitudes suggesting that both age and growth rate contribute to the sexual difference in body size because annual growth rates as well as age were higher in females than males.