A hoax as old as time

The recent Bigfoot fraud was remarkable for the naivety of its perpetrators. However, bringing the scientifically suspect to the public has led occasionally to new discoveries, but scientists are scared of being fooled.

This world-famous photo of the Loch Ness monster in Scotland was revealed as a fake 60 years after it was taken.

As hoaxes go, it was hardly sophisticated. Earlier this month, two hikers claimed to have found a dead specimen of the legendary apelike creature Bigfoot in a wood in the US state of Georgia. Last week, the corpse turned out to be a rubber gorilla suit with some fake entrails dumped on it. The only real mystery behind the stunt is how its perpetrators ever hoped to get away with something quite so ludicrous. Such hoaxes are usually far more sophisticated, with those responsible going to impressive lengths to cover their tracks.

It took 60 years for the truth to emerge about the best-known image of Nessie, the prehistoric monster said to lurk in Scotland's Loch Ness. Taken in 1934 by a London-based doctor named R Kenneth Wilson, the so-called "Surgeon's Photograph" showing a long-necked beast was long regarded as the definitive image of Nessie. Then in 1994 journalist James Langton - now, a senior editor on The National - revealed that the photograph was a hoax, cooked up by Wilson and three accomplices. They had used a carved monster's head around 30cm tall glued to a toy submarine to create the image, carefully excluding any nearby objects against which to judge scale. Its association with a respectable doctor with no obvious motive for hoaxing also helped maintain the photograph's reputation.

Yet even experts can sometimes be fooled by relatively crude hoaxes - if they want to believe hard enough. In 1912, an amateur British geologist named Charles Dawson claimed to have found the remains of a new species of human near Piltdown Common in Sussex. Leading scientists seized on the discovery as proof of their theories of a "missing link" between humans and chimpanzees. Not until 1954 did it finally emerge that the Piltdown skull was a hoax, having been created from nothing more sophisticated than a medieval human skull and the jaw of an orang-utan.

Such stunts have given scientists a pathological fear of being hoaxed, and deterred most from taking seriously any claims for "cryptids", creatures apparently sighted many times, but for which solid scientific evidence does not exist. Which is a shame, as those that have taken such claims seriously have been rewarded with some dramatic discoveries. For example, it took a German army officer exploring the mountains of Rwanda to uncover the truth behind centuries-old reports of a colossal "ape-man" stalking this corner of the Dark Continent. In 1902, Captain Robert von Beringe sighted a group of the creatures, shot two and after enormous effort retrieved the huge body of one. He found himself looking at the first known example of a Mountain Gorilla, the largest of all primates. Weighing in at 250kg and with an arm-span of over two metres, they are the real-life prototypes for King Kong.

Another legend stepped out of the storybooks a few years later in Indonesia. Local tribesmen had long talked of some of the islands harbouring giant dinosaurlike creatures. Western experts paid little attention, insisting there could be no more large animals on Earth. They were forced to change their views when a Dutch soldier investigating the claims presented them with the beast the islanders had described: the Komodo dragon. Measuring up to three metres or so in length and weighing as much as 160kg, these meat-eating beasts may not be real dinosaurs, but they remain the largest known lizards on the planet.

One of their island homes is currently the focus of potentially the most astonishing cryptid discovery of all time: a race of hobbit-like creatures that once lived alongside humans - and may still do so today. In September 2003, a joint Australian-Indonesian team excavating a cave on the island of Flores found the remains of a human-like creature barely a metre in height with a tiny skull similar to that of a chimpanzee. Anatomical quirks prompted the team to declare that they had found an entirely new ancestor of modern human. They proposed the name Homo floresiensis - "Flores Man" - which the media immediately dumped in favour of "Hobbit Man".

Dating of the remnants suggested the creature had lived in the cave as recently as 12,000 years ago - by which time modern Homo sapiens had begun to colonise the island. The claim that Hobbit Man is an entirely new species of human remains highly controversial. Some leading anatomists insist that the bones are consistent with ancient examples of H. sapiens suffering from congenital abnormalities. What no one disputes, however, is that small, hobbit-like creatures once lived on Flores alongside modern humans. And for those familiar with the folklore of the island, that raises an intriguing possibility - as the hobbit-like creature found in the cave is eerily like the Ebu Gogo, an elflike creature said to have lived on the island.

According to a legend still circulating among the Nage people of central Flores, the Ebu Gogo (which literally means "the omnivorous grandmother") lived in caves and was short in stature, with long arms and little intelligence - all of which fits the profile of H. floresiensis. Stories of the creature suggest that it was living on Flores as recently as the early 1500s, when Portuguese traders arrived. One palaeontologist working on the island is reported to have heard villagers still talking about the Ebu Gogo as recently as the mid-1990s.

Of course, there is no shortage of legends about races of "little people", from the leprechauns of Ireland to the menehune of Hawaii. What makes the Ebu Gogo unique is the existence of bones of creatures matching their description. What is needed now is for some intrepid scientists to brave the jungle fastness of Fores - and the opprobrium of their peers - and search for evidence bridging the gap between the legend Ebu Gogo and the bones of Hobbit Man.

Robert Matthews is Visiting Reader in Science at Aston University, Birmingham, England