I belive chupacabera's are a genetic manipulation not a animal that has evolved over time..If you do some reserch on them the first sitings came out of Puerto Rico..
In Puerto Rico there's a top secret U.S military base..In 1995 there was an explosion at this supposed secret base and it was not long after that these critters started being seen and livestock started being drained of there blood..So in my opinion these beast's are a product of the U.S military..The explosion aloud some of them to escape.
The public know's that we can clone sheep...Just imagine what what they do with genetic engineering that they don't tell us about..