I never paid much attention to the chupacabra business. My main objection was that no one ever heard of the darn thing until the 1990s, and animals don't just appear out of nowhere on a populated (and long-inhabited) island like Puerto Rico.
Benjamin Radford doubts pretty much all the animals of cryptozoology, and sometimes I think he's too quick to close a file. But I'm with him on this one. Critters labeled chupacabra involve what you might call Type 1 (odd-looking canids) and Type 2 weird-looking predators with spines down their backs. Radford attributes Type 1 to oddball, often diseased canids, and Type 2 to the movie Species. He may be two for two here.