The nightly attacks by two man-eating lions terrified railway workers and brought construction to a halt in one of east Africa's most notorious onslaughts more than a hundred years ago. But the death toll, scientists now say, was not as high as previously thought.
Over nine months the two voracious hunters claimed 35 lives — no small figure, but much less than some accounts of as many as 135 victims.
It was 1898, when laborers from India and local natives building the Uganda Railroad across Kenya became the prey for the pair, a case that has been the subject of numerous accounts and at least three movies.
The death toll had been estimated at 28 railway workers and "scores of unfortunate African natives," with the total ranging as high as 135. Delay of the railroad was even subject to debate in Britain's House of Commons.
Scientists hoping to figure out the actual number of people eaten decided to study the remains of the two male lions, now on display at the Field Museum of Natural History in Chicago, testing the types of carbon and nitrogen in their teeth and hair.
Those chemical ratios were compared with the carbon and nitrogen found in modern lions in the region, in lions' normal prey animals and in humans.
Bones and teeth store carbon and nitrogen isotopes over long periods, while the ratios in hair change more rapidly, allowing the scientists to determine the long-term diet and how it changed in the lions' last months.
Humans made up at least half of the diet of one of the lions in the last months of his life, consuming at least 24 people, they concluded. The other lion had eaten 11 people, they found.
Researchers led by anthropologist Nathaniel J. Dominy and Justin D. Yeakel of the University of California, Santa Cruz, report in Tuesday's edition of Proceedings of the National Academy of Sciences.
They noted that estimates of the death toll reported at the time ranged from 28 reported by the Ugandan Railway Company, to 135, claimed by Lt. Col. John H. Patterson, a British officer who killed the lions in December 1898.
The researchers did note that their study covers only the number of people eaten, while the number killed may have been higher. They said the death toll may have been as high as 75.
The killings occurred at a time when drought and disease sharply reduced the number of grazing animals that are the normal food for the lions, the report added, while at the same time construction of the railway brought an increased number of people into the area.
In addition, the researchers said the two lions seem to have cooperated in their hunting efforts. That's not unusual when they are after large prey like buffalo and zebra, but is not necessary when after something smaller, like people.
However, one of the lions had severe dental problems and a jaw injury, probably limiting his ability to hunt, they reported. So the two may have worked together, with one eating more people and the other concentrating more heavily on other prey, but also eating humans.
"These findings underscore the complexity of what lions are capable of doing, and the complex interplay of costs and benefits that determine the size of their coalitions," Dominy said in a statement.
The research was funded by the Earthwatch Institute, the David and Lucille Packard Foundation and the UC-Santa Cruz Committee on Research.