The Chinese water deer, Hydropotes inermis—A fast-growing and productive ruminant

The Chinese water deer is the most prolific ruminant. The species probably shows other characteristics favouring high productivity and population dynamics. Data on growth, maturity, reproduction and length of life were collected by monitoring a large semi-wild population for 3 years. These data were compared with those known for eight large rodents and 22 other artiodactyls of similar body size. Values for the longevity and age at sexual maturity of water deer are among the lowest of artiodactyls. The young grow faster than most other species and are the most precocious in terms of their age at weaning and at the end of the eruption of most molars. Lastly, both death rate and the renewal of individuals in the population are higher. The water deer appears to be by far the most dynamic ruminant, comparable to large rodents. This enables the species to colonize new areas rapidly. The peculiarities of the water deer fit with other morphological and anatomical features and can be considered as retained ancestral characters. A plausible explanation could lie in the ecological plasticity of the species.