Like muntjac, which also come from the Far East, water deer were imported into England during the 19th century. There were a few at London Zoo during the 1870s, but their main early stronghold was Woburn Park, where the 11th Duke of Bedford established a herd in 1896. Since then, through escapes and deliberate introductions, they have spread north-eastwards into low- lying parts of East Anglia; but unlike muntjac, which were also brought in by the Duke, and have now colonised much of England, water deer have never got going on a large scale.
So far they have remained largely mysterious creatures; but now two dedicated researchers have brought out an excellent booklet which describes their biology, behaviour and distribution. One of the authors, Dr Arnold Cooke, is by training a herpetologist (reptile and amphibian expert) and a specialist on pollution, working for English Nature, but he has spent more than 20 years studying deer, and is an expert on the way in which excessive numbers can damage the environment. His co-author Lynne Farrell, also a biologist, was a colleague of his at English Nature, and is now with Scottish Natural Heritage. Their main study area has been the Woodwalton Fen national nature reserve in Cambridgeshire, which includes large, wet areas dominated by reeds and sallow carr.
Water deer stand only about 20in at the shoulder, and in poor light can easily be mistaken for muntjac, which is about the same size. They are unique in several respects, not least in that females give birth to as many as seven fawns in a litter (other deer produce one at a time, or at most twins).
Hydropotes inermis is thought to be the most primitive form of deer in existence. The second half of its Latin name, meaning "unarmed", points to the fact that neither males nor females have antlers. Yet bucks do carry strange weapons in the form of sharp, curved tusks about 3in long, which sweep downwards from their upper jaws. These canine teeth are loose in their sockets, so that the owner can turn them backwards, out of the way, while he is eating, but swing them forward into an offensive posture if he is shaping for a fight. (Battles between males are common, and many animals carry ripped ears or other scars.)
The tusks give bucks quite a formidable appearance, and the first water deer recorded in the Monks Wood area of Cambridgeshire was described to the police as a lion. As the booklet records, the report "provoked considerable activity" until, later the same day, the animal was hit by a car and killed.
Another peculiarity of the bucks is the noise they make when chasing off rivals during the annual rut. Nobody is sure how they make the sound - variously described as "clicking", "whickering" or "chittering" - but it seems to emanate from the molars.
One minor mystery is why, with their phenomenal powers of reproduction, water deer have not increased and spread more quickly in this country. The authors suggest various reasons: many fawns die of hypothermia in infancy, and others are taken by foxes; adult animals are killed on roads, and some are shot. Yet muntjac, faced with similar hazards, have proliferated to such an extent that they have become a serious threat to conservation programmes.
In Monks Wood, for instance, only three miles from Woodwalton Fen, over- grazing by muntjac has brought about an ecological catastrophe: many of the ground flora - dog's mercury, orchids, primroses, bluebells - have been wiped out, and English Nature's attempts to restore areas of ancient coppice have been ruined by the deer persistently browsing off shoots from the hazel and ash stools, which cannot stand such treatment and eventually die.
Water deer are clearly here to stay, but not, everyone hopes, in excessive numbers. The booklet draws interesting comparisons with the status of the deer in China. There, a century ago, they were so widespread that they were regarded as an agricultural pest. Today poaching and loss of habitat have reduced numbers drastically, and the deer have been placed in Class Two of protected animals. Unless better conservation measures are introduced, the authors suggest, "the time may come when more of the Chinese subspecies live in England than in China", and English stock may have to be reintroduced to its native range.
`Chinese Water Deer' is the fourth in a series of booklets on deer published jointly by the Mammal Society and the British Deer Society. Copies, price pounds 3 each inc p&p, are available from The Mammal Society, 15 Cloisters Business Centre, 8 Battersea Park Road, London SW8 4BG (0171-498 4358).