The Water Deer (Hydropotes inermis) is a usually solitary animal, besides the rutting months, and a good swimmer. There exist two subspecies: the Chinese Water Deer (Hydropotes inermis inermis) and the Korean Water Deer (Hydropotes inermis argyropus).
Viruses lack most of the internal structure and machinery which characterize 'life', including the biosynthetic machinery that is necessary for reproduction. In order for a virus to replicate it must infect a suitable host cell.
Viruses do not fit the definition of living organisms. Viruses are molecular aggregates of proteins and nucleic acids (see Chapter 2) and lack cells or metabolic systems. Furthermore, although viruses self-replicate, they can only do so by using materials from their hosts, and they are only able to multiply inside host cells.