Two Lions Went on a Man-Eating Spree in 1898. Now, DNA Evidence Reveals Their Diets

In 1898, a pair of maneless male lions began terrorizing crews building the Kenya-Uganda Railway, killing and eating dozens of men over a span of about nine months. The lions became known as the “man-eaters of Tsavo” for their apparent dietary preference for humans, who they snatched from the railway camp at night.

John Henry Patterson, a railway administrator and a lieutenant colonel in the British Army, eventually shot and killed the two creatures, then wrote a book about the ordeal. The big cats’ bodies have been housed at the Field Museum of Natural History in Chicago since 1925.

Now, thanks to advances in ancient DNA analysis, scientists have used hairs found in the lions’ teeth to glean new insights into their diets. The team shared their findings in a new paper published last week in the journal Current Biology.

By extracting and studying DNA from the hairs, scientists determined the two lions feasted on giraffe, waterbuck, zebra, oryx, wildebeest—and, yes, several humans.

“What strikes me about the Tsavo story is that it is almost incomprehensible to a 21st-century Western mindset,” says Ross Barnett, a paleogeneticist at the University of Copenhagen who was not involved with the research, to the New York Times’ Jack Tamisiea. “The terror that the night must have brought is unimaginable.”

The discovery of human DNA wasn’t all that revelatory—the lions got their man-eater nickname for a good reason. But scientists were surprised to learn the lions had hunted wildebeest, too.

That’s because the closest wildebeest grazing area was more than 50 miles from the lions’ territory. Either the big cats were traveling farther than scientists had given them credit for, or the region’s historic wildebeest distribution looked different from what they had assumed.

If the lions were roaming far and wide, that finding would support historical accounts that the duo temporarily left the railway camp for roughly six months before returning and continuing to eat the workers.

Another surprise was the near-total absence of hairs from buffalo, which is a favorite food of today’s lions in the Tsavo region of Kenya. The 19th-century lions may have been unable to find buffalo because of rinderpest, a disease that spread through the area in the 1890s and decimated cattle and buffalo populations.

Experts had long posited that the two lions were brothers—and the latest round of research confirmed that theory using mitochondrial DNA. The fact that they had each other’s DNA in their teeth suggests the lions were closely bonded and spent time grooming one another, reports CNN’s Ashley Strickland.

Among the hairs, scientists found DNA that belonged to several humans. But until they can work with local communities and institutions, the team has no plans to reveal their identities. According to some estimates, the lions may have eaten as many as 135 humans. But a 2009 study suggested the total was much lower, likely around 35 individuals.

“There are potentially descendants, or a descendant community that may or may not want this type of analysis done, or maybe they do—we just don’t know yet,” says study co-author Ripan S. Malhi, an anthropological geneticist at the University of Illinois, to Nature News’ Emma Marris.

It’s still not clear why the lions were targeting humans. But scientists have a few theories. An analysis of the creatures’ jaws revealed they likely suffered from painful dental injuries while they were still alive. These injuries may have made it difficult for the big cats to hunt and eat large prey—humans may have been easy targets. A 2017 study of their teeth suggested the lions were primarily eating soft foods.

“Humans were a food of last resort, and the lions were primarily focused on the soft parts,” wrote Riley Black for Smithsonian magazine in 2017. “These were not devilish skeleton crunchers, but injured cats doing what they could to survive.”

Another possibility is that the lions were simply hungry because much of their normal prey had been wiped out by rinderpest. They may also have gotten their taste for human flesh from scavenging the corpses of enslaved people left behind by caravans that traveled through Tsavo on the way to Mombasa, Kenya, for centuries.

“The death rate was high; it was a bad area for sleeping sickness from the tsetse fly; and the bodies of slaves who died or were dying were left where they dropped,” Samuel Kasiki, deputy director of biodiversity research and monitoring with the Kenya Wildlife Service, told Smithsonian magazine’s Paul Raffaele in 2010.

Whatever the creatures’ motivations were more than a century ago, the new paper proves the value of hanging onto historic specimens.

“This study nicely exemplifies how much unique, hidden genetic information might be lurking in the crevice of a bone or artifact in a museum somewhere that’s just waiting for a clever researcher to ask an interesting question,” says Tyler James Murchie, a paleogenomicist at the Hakai Institute in Canada who was not involved with the paper, to Science News’ Jake Buehler.

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Sarah Kuta is a writer and editor based in Longmont, Colorado. She covers history, science, travel, food and beverage, sustainability, economics and other topics.