London, April 20: This is a story which goes back to 1898 when Indian workers shipped by the British to build the East African Railway from Mombasa in Kenya to Uganda in the interior were confronted with the demons of the night - people were being dragged out from their tents and their half-eaten bodies found in the morning.

At first, the Indians feared some of the locals were turning into rakhshas after midnight.

By and by, it transpired that the terror in Kenya's Tsavo region was being spread by two man-eating lions that were nicknamed the "Ghost" and the "Darkness" or "the man-eaters of Tsavo".

Lions normally go for large herbivores such as zebras, wildebeests and antelopes, and, if they are really hungry, giraffes, buffaloes and even elephants. But these lions had certainly developed a taste for fresh human flesh.

The reign of terror did not end until the lions were shot in December 1898 by a British hunter and railway engineer, Lt Col John Patterson, who, as was the custom of the time, posed proudly with his huge kills. The two lions were maneless, having apparently adapted to extreme heat.

The Uganda Railway reported 28 dead workers but Patterson put the figure at 135 and this included some Africans as well.

In the decades that followed, audiences were captivated by the story of the ferocious lions, told in countless newspaper articles, dozens of academic papers and books. The most vivid account came from Patterson himself in 1907 in The Man-Eaters of Tsavo.

He wrote about a particular night when "the brutes" seized a man and ate him close to his camp.

He recalled: "I could plainly hear them crunching the bones, and the sound of their dreadful purring filled the air and rang in my ears for days afterwards."

In 1924, the lions were sold as trophy rugs to the Field Museum of Natural History in Chicago where they were stuffed and have been on display ever since.

The tale of the man-eaters of Tsavo has been turned into three films, most notably in 1996 when Hollywood made The Ghost and the Darkness, starring Michael Douglas and Val Kilmer as the heroes and the late Om Puri, being Indian, in a negative role.

The film's screenwriter, William Goldman, told the Los Angeles Daily News of the lions: "My particular feeling is that they were evil. I believe that for nine months, evil popped out of the ground at Tsavo."

The film won an Oscar for sound editing.

There the tale would have remained, the stuff of legend, except that with the lion rugs, Patterson also fortuitously provided the two skulls - and recent analyses done on them by biological scientists have just been published in the US journal, Scientific Reports.

They indicate that severe dental disease, which made it very painful for the lions to break the bones of their normal prey, made them more like zoo animals that are fed relatively soft beef and horse meat. In the case of the Tsavo lions, they found Indian workers constituted easy pickings, especially as a drought in the region had reduced available food.

"There's really something about 'man-eaters' that puts people in their rightful place," noted Bruce Patterson (no relation to Lt Col Patterson), a co-author of the new paper and the curator of the mammal collection at Chicago's Field Museum of Natural History. "Not at the helm but a couple of notches down."

As a mammalogist, Patterson oversees some 230,000 specimens.

"Few have stories to tell that are as exciting as these two," he told American newspapers.

His examination of those skulls showed that the dominant member of the Tsavo duo, the lion probably responsible for killing more humans, was missing several teeth. He also had a severe tooth abscess.

Lions frequently break their teeth if grazing animals respond to the cats' face-first lunges with hoofed kicks. But abscesses and more grievous injuries are rare. The pus pocket may have made it too painful for the Tsavo lion to subdue typical prey, an explanation that Patterson quipped was the "smoking gum".

For the most recent study, Patterson and a colleague, Larisa DeSantis of Vanderbilt University, pored over the lions' teeth, analysing their dental microstructures. The scientists compared the Tsavo lions' teeth to those of zoo lions, wild lions, cheetahs and known bone-crunchers such as hyenas.

"The Tsavo lions' teeth do not show wear patterns consistent with eating bones," commented DeSantis. "In fact, the wear patterns on their teeth are strikingly similar to those of zoo lions that are typically provisioned with soft foods like beef and horse meat."

Then, how did Lt Col Patterson hear the bones being crunched? The scientists feel it may just have been the sound the lions made as they tore into the flesh.

The analysis ruled out the hypotheses that the lions developed a taste for humans by scavenging on dead bodies, in the scientists' view. Scavengers eat the bones of bodies that are not freshly killed, either because the flesh has decayed or something else picked at it first.

As the researchers concluded in the new report, "the man-eating lions consumed softer parts of humans and other prey and did not fully consume carcasses".

Patterson said: "It's remarkably rare for lions to attack people, but it's catastrophic when it happens. When a big, dangerous predator becomes incapacitated, there's a real danger for this kind of behaviour - no animal will let itself starve to death if there's another option."

While reports of people being eaten are uncommon today, this could change, the researchers warned.