Chicago Field Museum

Analysis of the teeth of the man-eating lions of Tsavo suggests it wasn't dire circumstances but dental disease that drove the legendary lions to eat an estimated 35 people in Kenya in the late 1800s, a new study reports.

Why it matters: The findings reveal the many factors that can influence lion behavior and could inform conservation efforts. As human populations increase and prey decreases, man-eating could become a viable option for lions, the researchers wrote.

Lions rarely eat humans. The theory had long been that when they do, it's because of a shortage of prey — caused, in the case of the Tsavo lions, by a drought. The new findings suggest humans can be an easy alternative to supplement a lion's diet whether there are prey shortages or a lion is injured.

Methodology: Researchers from Chicago's Field Museum, where the two lions are part of the collection, and Vanderbilt University analyzed the surface of the lion's teeth with 3D imaging for wear associated with their diet. They compared them to zoo lions, wild lions, cheetahs (which do not eat bones) and hyenas (which scavenge and eat entire carcasses). If the lions were desperate and scavenging for food, they expected to see evidence of bone-crunching on their teeth, similar to hyenas.

What they found: The Tsavo lion that ate the most people had a severe dental disease that would have made it difficult to hunt prey like zebra and buffalo. The microscopic patterns on the teeth of the man-eating lions were smooth and most similar to zoo lions, which are fed soft foods like beef, and cheetahs, indicating the Tsavo lions were not fully consuming carcasses.

Parting perspective:

"We don't like to think of ourselves on the menu but we are," -- Laura DeSantis, Vanderbilt University.

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