A good 120 years ago, two lions killed dozens of railway workers in what is now Kenya. Hair from their victims is still stuck in the teeth of the now stuffed animals and provides material for DNA analysis. Why did they hunt people? Instead of a lack of prey, researchers from the USA have identified another reason.

In 1898, horror spread among bridge builders on the Tsavo River in Kenya. Two male lions kept coming into the camp at night, breaking into tents and kidnapping their victims. At least 28 people are said to have been killed. The story might sound familiar to some: the action film “The Mind and the Darkness” (1997) starring Val Kilmer and Michael Douglas is about it.

Thousands of hairs in dandelion cavities contain ancient DNA

The lions of Tsavo are now stuffed in the US Field Museum of Natural History seen in Chicago. Researchers have found, among other things, human hair in damaged lion teeth and analyzed it genetically.

The workers on the Tsavo River in the southeast of what is now Kenya were busy building the Kenya-Uganda railway. The “Lions of Tsavo” killed people for months until British Lieutenant Colonel John Patterson managed to kill them. He sold the remains of the maneless males to the museum in 1925. Both have a number of damaged teeth, including partially broken canines.

Two maneless lions that now live in the Tsavo region. Photo: Michael Jeffords and Susan Post/dpa

The analysis revealed that a total of thousands of hairs are embedded in compacted layers in the cavities of these teeth. The researchers led by Tom Gnoske from the Field Museum report in the specialist journal that they have succeeded in developing a method for extracting and analyzing DNA from individual hairs that are more than 125 years old „Current Biology“.

DNA extracted from tiny fragments

They concentrated on so-called mitochondrial DNA, among other things because it is better preserved in hair. There were also microscopic analyses.

The DNA in the hair shafts and tiny clumps of hair fragments was degraded in a manner typical of historical DNA. In some of the samples, however, enough of it could be reassembled, the scientists write.

“We were even able to extract DNA from fragments shorter than the nail of your little finger,” explains co-author Alida de Flamingh from the University of Illinois Urbana-Champaign.

The team included Thomas Gnoske (front row, far left), Julian Kerbis Peterhans (front row, far right) and Samuel Andanje (back row, second from left). Photo: dpa/Photo 77104 copyright Thomas Gnoske, 1997

Some of the hair comes from lion victims

According to the research, some of the hair comes from the lions’ numerous human victims. Hair from giraffes, oryxes, waterbucks, wildebeests and zebras could also be identified. The DNA analyzes also showed that the two males were siblings who came from what is now Kenya or Tanzania.

Face of a lion with blood spatters. Photo: dpa/Michael Jeffords and Susan Post

What was surprising for the team around Gnoske and de Flamingh was that they found wildebeest hair. “This suggests that the Tsavo lions either traveled further than previously thought or that there were wildebeest in the Tsavo region at that time,” reports Alida de Flamingh. “The nearest wildebeest grazing area was more than 80 kilometers from where the lions were killed in 1898 at the confluence of the Tsavo and Athi rivers.”

However, it is also known from historical reports that the two male lions left the Tsavo region for about six months before they attacked the bridge builders’ camp again. The wildebeest hair may come from this phase.

Zebras (above) and wildebeest Photo: dpa/Michael Jeffords and Susan Post

Why no buffalo hair was found

The researchers were also surprised that they found no buffalo DNA and only a single buffalo hair. “From what the lions in Tsavo eat today, we know that buffalo are their preferred prey,” emphasizes Alida de Flamingh. Lt. Col. Patterson kept a handwritten field diary during his time in Tsavo that never mentioned buffalo or local cattle, they say.

As a possible explanation, the researchers suggest that rinderpest, which was introduced from India in the early 1880s, was circulating in this part of Africa at that time. “It almost completely wiped out cattle and their wild relatives, including Cape buffalo,” explains co-author Kerbis Peterhans of the Field Museum and Roosevelt University in Chicago.

This is what the lions might have looked like while hunting a wildebeest. Photo: dpa

Reconstruction of nutrition

The research group now wants to try to reconstruct the diet of the male lions over time. Among other things, to clarify when they started hunting people. The new method is certainly also useful for analyzing prey DNA from other ancient animal skulls and teeth. It could possibly still be used with samples that are thousands of years old.

Studies of the teeth of the Tsavo lions had suggested in previous analyzes that dental injuries, along with factors such as limited availability of prey, led to the two males becoming man-eaters.

This is what the lions might have looked like while hunting a giraffe. Photo: dpa/ainting copyright Velizar Simeonovski, 2024

One of the lions suffered from a root infection

One of the lions was discovered to have a root infection that made normal hunting impossible, Larisa DeSantis of Vanderbilt University in Nashville and Bruce Patterson of the Field Museum reported in 2017 „Scientific Reports“reported. Attacks on largely defenseless people who were easy to bite were much more pleasant for him.

A third lion, which is said to have eaten at least six people in Zambia in 1991, was also found to have dental problems. There are also cases known from India in which weakened leopards and tigers switched to humans because they are easier to kill.

The researchers also used special methods to find out what the animals ate in the days and weeks before their death. The second Tsavo lion had healthier teeth and also hunted and ate zebras and buffaloes and fewer people, the researchers explain. This speaks against food shortages as a reason for the attacks on the track workers.