I have lived in Chile, South America for a number of years and some time ago we had an attack from what they called the "chupacabra". No one ever saw it, but it would attack a herd of animals and leave a number of them dead just by sucking their blood. The next morning the owners would find them on the ground with a little hole in their neck area. The attacks finally stopped on their own and we've not had anymore problems. It made us wonder if it wasn't a person doing it and draining the blood into something instead of an animal.