Suggested Jersey Devil Bat By Jay Cooney
This theory would depend on some unknown person to release captive African bats into the wild in New Jersey and for the bats to thrive long enough to be regularly sighted.
My more recent theory is that they are Chupbats which arw very like False Vampire bats but at twice the length and twice the wingspan: this fits the size requirements since this matches the hammerheaded vbart very well, but the diet is not restricted to tropical fruits that would be hard to come by in the wilds of New Jersey. The false vampire bats eat birds and the chupabats seem to regularly attack domesticated poultry. This also fits because the Jersey Devils have long been blamed for killings of domesticated animals in much the same fashion as the regular Chupacabras (Devil Bat/El Vampiro) reports throughout Latin America.
Source: aquarius-project.blogspot.com