Two of America's mysterious creatures have recently reared their furry heads: Bigfoot and the goat-sucking chupacabra.
On Sept. 16, 2007, a hunter in the Allegheny National Forest got photos of what some claim is a Bigfoot. The hunter had fastened a remote-trigger camera to a tree and when he returned he was surprised by images of a dark, four-legged animal that he did not recognize.
A spokesman for a group of calling itself the Bigfoot Field Researchers Organization examined the photos and concluded that it was probably not a bear, as some had suspected. Instead he said, "It appears to be a juvenile Sasquatch." It was a pretty bold assertion—a genuine Bigfoot photograph! —based on an unclear photo. According to experts the group consulted (unnamed "zoo people"), "this figure looks much more like a healthy primate" than a thin bear.
Yet actual experts, such as Jerry Feaser of the Pennsylvania Game Commission, noted that wilderness officials who work with bears see such animals every now and then. Instead of a juvenile Bigfoot, it is in fact a bear in poor health. (The fact that the "Bigfoot" was photographed in the presence of bear cubs was another clue....)
In July, a rancher in the small Texas town of Cuero captured a strange doglike creature that had been attacking her livestock. She said the blue, hairless animal had been lurking around her ranch for years. When it was finally killed by a car, she claimed to have finally captured a chupacabra, the vampiric monster of Hispanic lore. The creature was beheaded, and tissue samples sent to biologists at Texas State University for DNA analysis.
The results were made public just after Halloween: the creature was not a chupacabra. It was not even a grey fox, as some had suspected. It was instead a Texas coyote.
How could a hunter not recognize a bear, or a rancher not recognize a coyote?
What these two animals have in common (other than being mistaken for possibly mythical creatures) is a bad case of mange. Mange is a parasitic skin infection caused by mites. Animals afflicted with mange often look strange, either hairless or partly hairless. Sarcoptic mange, a highly contagious form of the disease, can cause hair loss as well as extensive skin welts and crusting.
Because people usually see animals with their full coat of fur, animals with mange can be difficult to identify. A polar bear afflicted with mange might be totally unrecognizable, due to the odd patches of white fur on its black skin.
In addition to mange, feral animals may have other associated health problems and diseases that help to create an unnatural appearance. A juvenile coyote, for example, whose growth has been stunted by a lack of food might appear about the size of a small dog, yet not share the distinctive features of a dog.
Real proof that Bigfoot or chupacabra exist remains elusive. But what these cases—and many others—prove beyond any doubt is that people mistake bears for Bigfoot, and coyotes for chupacabra.
Benjamin Radford is LiveScience's Bad Science columnist and managing editor of Skeptical Inquirer science magazine. His books and films can be found on his website.