Sigbin, the Philippines' Chupacabra

The Philippines has its own vampiric cryptid known as the Sigbin, which is very similar to the Chupacabra.  The Sigbin is said to be a creature of the night that feeds on the blood of its prey through their shadow.  It resembles a hornless goat or kangaroo-like creature with large ears, has a long, whip-like tail, and exudes a nauseating odor.  Its wide mouth holds large, wicked fangs.

Much like many believe that folklore surrounding the Chupacabra arose out of misidentified mangy coyotes and wild dogs, so too is there speculation of a mundane explanation for the Sigbin.  The recently-discovered cat-fox in Borneo has skeptics wondering if perhaps the possible carnivore, or a related species, is responsible for sightings of the Sigbin.  Cat-foxes are described as having hind legs longer than their front ones, red fur, and a long tail; all features that, at least superficially, can be attributed to the Sigbin.  

Could the legends of the Sigbin and the Chupacabra have arisen out of misidentified sightings of mundane animals?  Are their supernatural similarities simply a function of the archetypes common across human culture?  Or is there some undiscovered creature--natural or paranormal--that is feeding on blood and terrifying witnesses in the Philippines, North America, and across the world?

Tobias Wayland