Ecological and morphofunctional features of the water deer (Hydropotes inermis): A new species in the fauna of Russia

Aim. To summarise the available data on the ecology and morphology of the water deer (Hydropotes inermis Swinhoe, 1870).The water deer is the most primitive in the deer family (Cervidae Goldfuss, 1820) and has the greatest morphological similarity with the extinct Dremotheriinae. A phylogenetic tree of the mitochondrial cytochrome b gene shows the proximity of the water deer to roe deer (Capreolus Gray, 1821) and muntjacs (Muntiacus Rafinesque, 1815). A number of morphofunctional characteristics of the water deer contribute to its habitat in waterlogged habitats. The modern range of H. inermis is fragmented: the Chinese subspecies inhabits the lower reaches of the Yangtze River, while the Korean one – on the Korean Peninsula is actively expanding its range to the adjacent territories. The paper discusses the expansion of the water deer in the south of the Primorsky krai, provides data on the nutrition, reproduction and population dynamics of this species here as well as potential problems in the field of biosafety.A stable population of water deer has formed in the south of the Primorsky krai. The size of this population continues to increase due to the high productivity of this species, the availability of sufficient fodder, places for shelters and the consistently improved system of protection of natural territories in Russia, China and North Korea. The water deer can be considered as a reserve element of the food resource for the large felines of IUNC Red List. It is necessary to intensify zoological studies of this species and combine them with comprehensive ecological, virological and parasitological monitoring.