Scientists could not have found a better time than Halloween to explain the tales of the mysterious blood sucking monster chupacabra, or chupacabras that has been doing the rounds in US, Mexico and even China since the mid-1990s. The first case was reported in Puerto Rico.

The chupacabras have allegedly been found as recently as June—making the flesh and blood monsters eminently more accessible for study. In most cases, the monsters have turned out to be coyotes suffering from the worst case of mange, a painful, potentially fatal skin disease that ultimately cause baldness and skin shriveling.

Barry OConnor, a University of Michigan entomologist who has studied Sarcoptes scabiei, said the parasite that causes mange said there is no need to look for any further observation, according to National Geographic.

Wildlife-disease specialist Kevin Keel has also seen images of an alleged chupacabra corpse and recognized it as a coyote. But for a layperson, this might be confusing as they indeed looked very different.

The scientists have explained that Sarcoptes scabiei also causes the itchy rashes in humans and non-humans as well where the mites burrows under the skin of its host and secretes eggs and waste material that trigger inflammation of the skin. While, scabies is a minor irritant in comparison, mange can be life threatening for canines such as coyotes, which haven't evolved especially effective reactions to Sarcoptes infection.

The University of Michigan's OConnor speculates that the mite might have passed from humans to domestic dogs, and then on to coyotes, foxes, and wolves in the wild.Further explaining the evolution process, he said, primates are the original hosts of the mite. Human body can keep scabies under check because of the evolutionary connection with the primates but other animals cannot cope with it.

“Animals with mange are often quite debilitated," OConnor said. And if they face difficulty in finding prey, they might chose livestock, because it's easier, he added.