Why did the Tsavo lions eat people? Possibly because we’re soft
No one knows exactly how many people the two lions consumed between March and December 1898, when a British soldier shot and killed the deadly pair near Kenya’s Tsavo River. The Ugandan Railway Co. reported 28 dead workers. Lt. Col. John Henry Patterson, the Irishborn adventurer who shot the lions, wrote that the lions ate 135 people. (He had a book to sell.) More than a hundred years later, a chemical analysis of the lions’ hides suggested that they ate about 35 people, with the most likely tally falling between four and 72 ingested.
Speculators and scientists have long wondered why these lions ate humans — most lions do not. The cats inspired three Hollywood movies, dozens of academic papers and countless newspaper articles. Their bones and skins continue to provide information, in finer and finer detail.
A study published Wednesday in the journal Scientific Reports took a microscopic look at the grooves on the lions’ fangs. Their analysis suggests that the lions likely preferred hunting live humans because they were softer than gnawing on dead bones.
“There’s really something about ‘man-eaters’ that puts people in their rightful place,” said Bruce Patterson (no relation to the 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 at the Field Museum, Patterson oversees some 230,000 specimens.
“Few have stories to tell that are as exciting as these two,” he said. When the museum bought the lions in 1925, the animals arrived splayed out as rugs. The rug-maker kept the cats’ skulls within their skins, a fortuitous decision for researchers such as Patterson.
In 2000, Patterson’s 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, Patterson said, 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.”
Even with broken teeth, lions are flexible eaters. Perhaps the Tsavo lions first had to scavenge on corpses, he suggested, and only then began to hunt the living. In 1898, bodies would have been common: First, a severe drought struck the region, killing livestock herds and herders alike. Second, a virus called rinderpest felled cattle and their wild relatives, including common lion prey such as buffalo, making the lions desperate for new sources of food. And third, the British engineers planned the railway along a caravan route that brought slaves from Uganda and the Congo to the coast.
“This caravan trail would have left a steady trail of dead and dying slaves,” Patterson said.
For the most recent study, Patterson and a colleague, Vanderbilt University’s Larisa DeSantis, pored over the lion teeth, analyzing 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 were most similar to those of captive animals. Zoos provide lions with slabs of horsemeat or beef, Patterson said, and only rarely give the cats access to carcasses. Likewise, cheetahs, which do not eat bones, showed similar wear on their teeth to the Tsavo lions’ grooves.
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.