Well this was a surprise. I was in Titchwell Marsh, an RSPB reserve in Norfolk, looking for ducks and waders and so on, as one does, when I came across this strange-looking deer. It is a Chinese water deer (Hydropotes inermis). It looks to me as though the front half and back half belong to different sized animals, rather like a mis-matched pantomime horse.
Chinese water deer were introduced to London Zoo in 1873 and later to Woburn and to Whipsnade Zoo. Some deer escaped from Whipsnade before the war and are now well established in the damper parts of Buckinghamshire, Cambridgeshire, and Norfolk. Their preferred habitat is reed beds and dense waterside vegetation so they are unlikely to spread much more widely. The males, like this one, have tusks instead of horns and they use them for fighting. In their home in the Far East their survival is threatened and the UK now has 10% of the world population.
Male water deer are fiercely territorial and fights are frequent although fatalities are rare. Look closely and you can see that this one has torn ears and missing fur and long scratch marks on his back. I guess he was fighting with a stronger rival and came off worse. His tusks are relatively small so he may be younger or less well armed than the others.