The chupacabra or chupacabras is a legendary creature in the folklore of parts of the Americas, with its first purported sightings reported in Puerto Rico. The name comes from the animal's reported habit of attacking and drinking the blood of livestock, including goats. Physical descriptions of the creature vary.

Why only the goats?

Most people ask why do chupacabras only suck the blood of goats, well the meaning of the name is an animal said to exist in parts of Latin America, where it supposedly attacks animals, especially goats.

Is this creature real?

Well no one is sure we have some evidence but they always can lead to it being a coyote or a wolf or even a stray dog no one knows at all. People say they have caught one but never say what it looks like or a description on the creature.

This is what man and woman believe the chupacabra looks like but no one is sure.

Tales of the chupacabra first emerged in Puerto Rico in the late 1990s. They described a bipedal creature four or five feet tall with large eyes, spikes down its back and long claws. This beast, people claimed, was responsible for killing and draining the blood of livestock, an act that earned it its name – which is Spanish for "goat-sucker".

This is what first drew Benjamin Radford to the chupacabra, a supposedly vampire-like creature. Its roots are in Latin America, but stories about it have since spread to the rest of the world, including his native New Mexico.

"This was a much more local mystery to me," says Radford. "I didn't have to go to Inverness or Borneo, it was right here in my backyard." Helpfully, the chupacabra also seemed to be less shy than your average monster. That meant Radford had a good chance of figuring out whether or not it was real.

Radford's extensive investigation took five years (Credit: Benjamin Radford)

In his extensive investigation, which took a total of five years and saw him travel as far as the jungles of Nicaragua, Radford even located the person who first reported this beast: chupacabra patient zero.

Her name is Madelyne Tolentino and she comes from Canóvanas, a town in the east of Puerto Rico. In 1995, she spotted a scary alien-like creature out of her window.

What is remarkable is how fast the story travelled. After more reported sightings, and links made subsequently in the media with livestock that had been found "drained of blood", the legend of the chupacabra spiralled out of control. First it spread around the island, then the rest of Latin America and into the southern US states. It also flourished online, where it was latched onto by UFO enthusiasts and conspiracy theorists. When Radford, a research fellow with the Committee for Skeptical Inquiry got wind of this story, he recognised a unique opportunity. Between the dead livestock and the actual specimens, he had the makings of an unprecedented scientific investigation into a creature that had already achieved infamy on a par with Bigfoot or the Loch Ness monster. This was a story he could really get his teeth into.

"When you have a body, everything changes," he explains. "You have DNA samples, you have bone samples, you have morphology." As with all his missions, Radford approached the chupacabra with an open mind, employing what he calls "investigative scepticism", conducting field work, collecting evidence and interviewing witnesses.

"I was of course initially sceptical of the creature's existence," he says. "At the same time I was mindful that new animals have yet to be discovered. I didn't want to just debunk or dismiss it. If the chupacabra is real, I wanted to find it."

Radford and a colleague tracking the elusive beast
Radford and a colleague tracking the elusive beast (Credit: Benjamin Radford)
The obvious place to start was with the chupacabra bodies. These have mostly turned up in Texas and other south-western US states, and Radford has recorded about a dozen in total. They are quite horrific-looking: hairless, with a gaunt appearance and burnt-looking skin.

However, DNA tests revealed a pretty mundane reality. The bodies have invariably turned out to be coyotes, dogs or raccoons – barring one that was actually a fish.

The reason these animals get identified as chupacabras is because they've lost their hair owing to sarcoptic mange

But despite clear DNA evidence, this version of events is a little fishy. The people who found and often shot these creatures were usually ranchers or rural folk who should recognise a coyote when they see one. So where does this confusion come from?

"The reason these animals get identified as chupacabras is because they've lost their hair owing to sarcoptic mange," explains Radford.

Sarcoptic mange is caused by itch-inducing mites called Sarcoptes scabei burrowing into the upper layer of the skin. It is very common. Alison Diesel of Texas A&M University, US, who specialises in inflammatory skin conditions in animals, agrees that this disease can be sufficiently gruesome to produce convincing monsters.

"The 'mangy dog' is typically very sparsely haired to near-bald, with red or hyper-pigmented black, thickened skin," she explains. Add to this the self-inflicted wounds from scratching and a hairless body, and you have yourself a "chupacabra".

Animals with mange are gaunt and start to lose their fur (Credit: Nature/Alamy)
Animals with mange are gaunt and start to lose their fur (Credit: Nature/Alamy)
Sarcoptes mites are thought to have infested humans for hundreds of thousands of years, but in more recent evolutionary history made the transition to dogs and other similar animals. This could explain why scabies in humans – the minor rash that results from the mites burrowing into our skin – is a relatively trivial affair, whereas in dogs it can cause death. These animals might not have had long enough to evolve an effective immune response to the mites.

Blood feeders are looking for blood that's close to the surface of the skin

But the chupacabras are only half the story. "There are two sets of bodies here," says Radford. There are also the reports of dead livestock. "Something is attacking these things, leaving puncture marks on their neck and supposedly draining their [bodies] of every drop [of blood]. So what's going on there?"

The answer, once again, is surprisingly straightforward. These animals are most likely the victims of ordinary predators, such as dogs or other canids. It is not uncommon for a dog to bite an animal in the neck and then leave it. Quite often the animal will then die from internal haemorrhaging, with no other injuries apart from puncture marks.

And while, thanks to Dracula, puncture marks in the neck tend to be associated with vampires, Bill Schutt of the American Museum of Natural History in New York, US, says unequivocally that this is not how real-world blood-sucking creatures actually behave.

"Blood feeders are looking for blood that's close to the surface of the skin, something not found in a jugular vein for example," he says.

These mites cause mange (Credit: Natural History Museum/Alamy)
These mites cause mange (Credit: Natural History Museum/Alamy)
In fact, if we compare the characteristics of real blood-feeding animals such as vampire bats with those of the chupacabra, there are hardly any similarities. Vampires, according to Schutt, are small and stealthy, with specialised teeth and digestive systems that allow them to extract nutrients from blood.

A creature the size of a dog "would starve to death pretty quickly on a blood meal," he says, owing to the lack of essential components such as fat.

When an animal dies, the heart and blood pressure stop

Besides the presence of these "tell-tale" bite marks, Radford thinks he knows why worried ranchers might attribute the death of their animals to a blood feeder. Having found a mysterious corpse, they would examine it and perhaps cut into it, expecting blood to spurt out – but they would be surprised.

"When an animal dies, the heart and blood pressure stop," he explains. "The blood seeps to the lowest part of the body, and it coagulates and thickens. It's called lividity, and it gives the illusion that they've been drained of blood."

So if all the mythology surrounding the chupacabra actually comes down to some fairly commonplace natural phenomena, why do the stories live on with such vehemence today?

There have been various descriptions of the chupacabra's appearance
There have been various descriptions of the chupacabra's appearance (Credit: Jamie Chirinos/SPL)
Bizarrely, Radford says it might have something to do with an anti-US sentiment found across Latin America. This is particularly true in Puerto Rico, which is in the unusual position of being a non-state territory of the US.

"I spoke to several Puerto Ricans who felt that the US had exploited, short-changed, and ignored the island, in economic and many other ways," he says. Most recently, this resentment has played out in the island's ongoing debt crisis.