The legend originated from the America's. The translation of the name is 'goat sucker'. The name comes from reports that the creature feeds off the blood of stock animals, especially that of goats. Whether this creature is only that of an urban legend or is truly something that science is yet to recognize is hard to say. Everyone's heard the saying that seeing is believing but I don't particularly trust video from the Internet. It can be warped to look like and sound like something it's not.
It has been speculated that parasite ridden coyotes could be the basis of this legend. With certain parasites causing hear loss on animals, others causing that animal to become anemic, I find that plausible. I am not however, ruling out the existence of this creature. It may be far fetched but I'm not one to be a skeptic without really knowing.
There have been many reported sightings of this animal, and it's been given many different names. It's up to you what you think about his legend. But even if there's a tiny amount of a possibility that science had missed this creature, it would have to make you wonder what else we don't know or understand.
As one of my favorite quotes says, 'The more I know, the more I know I don't know'.