The Fuzzy Chupacabra Hypothesis holds that this cryptid is most likely mammalian, not reptilian, not only for those reasons outlined in the Hominan Hypothesis, for the very simple reason that while we do have have no evidence of a blood drinking-reptile, nor any reptile in humanoid form, we do know of three species of blood-drinking mammals that see in the dark, with razor sharp teeth, Desmodus rotundus, Diphylla ecaudata, Diaemus youngi, otherwise known as infamous vampire bat.
Of course, bats aren’t the only mammals that drink blood. While many Homo sapiens enjoy eating blood in the form of sausages (black puddings and such), even more people enjoy drinking the nutritious fluid up in hearty broths, known as blood soups, of which there are at least a dozen.
But perhaps no people loves drinking blood more than the noble Maasai of the Rift Valley, herders whose who live quite happily on cow’s blood and milk. Delicious, if you ask me, and healthy too, according to very credible medical reports.
Thus, not only do we have proof of blood drinking mammals, but blood drinking hominans. So until some blood-drinking reptilian humanoid should cataloged, whether in high office or out in the wild, the most likely morphology for the beloved Chupacabra, based on the evidence we do have in hand at the present time, is to be hominoid of the family of the apes.