April 19 (UPI) -- In 1898, a pair of man-eating Tsavo lions killed and ate between 30 and 35 people working on the construction of the Kenya-Uganda Railway. The lions were eventually killed and the human-hunting ended.
Scientists have mostly assumed a dearth of suitable prey inspired the lions taste for human flesh, but new research suggests dental disease may have played a role.
In journal entries and letters, Lieutenant-Colonel John Henry Patterson, head of the railway construction project, described the sounds of lions consuming human outside his camp.
"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," he wrote.
Recently, scientists from Chicago's Field Museum and Vanderbilt University created dental casts of the lion's teeth. The researchers used 3D imaging technology to create detailed maps of the teeth's microstructures. Their analysis revealed little evidence of significant bone-crunching.
"The microscopic wear of the lions' teeth were less complex and 'chewed up' than you'd see in an animal that eats lots of bone, like a hyena. Instead, their dental microwear is similar to what you'd see in a zoo lion," Larisa DeSantis, a paleontologist at Vanderbilt, said in a news release.
DeSantis and her colleagues did, however, find evidence of dental disease.
Scientists found evidence of an abscess and infection at the root of a canine belonging to the Tsavo lion which previous studies suggested killed the most humans. Such an infection would have prevented the lion from hunting large prey.
"Lions normally use their jaws to grab prey like zebras and wildebeests and suffocate them," said Bruce Patterson, mammal curator at the Field Museum. "This lion would have been challenged to subdue and kill large, struggling prey, and humans are so much easier to catch."
The painful tooth infection may explain why the lions targeted humans, and also why the pair avoided chomping on bones.
Researchers shared their findings in the journal Scientific Reports.
"When a big, dangerous predator becomes incapacitated, there's a real danger for this kind of behavior -- no animal will let itself starve to death if there's another option," Patternson said.