i think it went down like this:

the original crazy chimaera/alien/paranormal sighting reports came out of puerto rico coupled with reports of a phenomenon -livestock animals apparently drained of blood- and because the public has no general concept of the fact that correlation is not causation, the creature and the phenomenon became linked and the the creature gained the name "goatsucker" (even though the first reported "victims" were sheep).

then a similar phenomenon surfaces in texas: apparently "sucked dry" livestock. enough people in texas speak/understand spanish that someone gets told a story and exclaims "el chupacabra!" but either doesn't know/doesn't relate the description of the original animal associated with the name.

then an "anomalous animal" (or at least one people aren't used to seeing) pops up in texas, and -again failing the correlation/causation concept- the good people of texas associate this apparent phenomenon with this different reported animal. wha-la! the "naked dog" chupa is born! (this is the way of mythology/folklore).

things to remember:

*we don't have real, conclusive evidence that all these poor "sucked dry" animals, anywhere, aren't victims of known forms of predation/scavenging/decomp.

*even if the livestock phenomenon is real, we have no evidence that either the "island version" or "mainland version" "chupas" are responsible for it.

in conclusion, i have no doubt that the "naked dog" chupas are real critters. i do have doubt that they are ultimately responsible (or solely responsible) for the "vampire killings". many of the doggie chupas are poor mangey coyotes. but i think it is very likely that a naturally hairless and dark skin-pigmented domestic dog breed (see the mexican and peruvian hairless dog pics in the other chupa thread, both of which have overland and human assisted access to texas) has bred itself into a slightly different mutt form in the texas wildlands, it may also have created a new and fertile hairless dog-coyote-wolf hybrid out there and formed a breeding population of "chupas".

now, the chimera chupa? that's a different (and in my mind improbable) kettle of monsters.