What did Savo’s ‘man-eating’ lions eat? Preserved hairs on their fangs reveal their diet

In the early 1990s, zoologist Thomas Gnoske identified two lion skulls in the archives of the Field Museum of Natural History in Chicago. These were the remains of a pair of adult men who in 1898 murdered about thirty people in Kenya, most of whom were Indian workers participating in the construction of a railway bridge over the Tsavo River. Felines, whose story was very popular in the newspapers of the time and was later told in film monsters of the nightIt became a fascinating subject of scientific research beginning in 2001, when the first analysis of the remains revealed new aspects that helped explain the strange behavior.

Among the details Gnoske saw in those first analyzes were thousands of fragmented and compacted hairs from their prey that had accumulated in the cavities of the lions’ broken teeth. “While examining them, I noticed that there were some small hairs stuck among other remains on the surface,” the researcher told elDiario.es. “That gave me a clue that there might be more material beneath the surface and that it probably reflects what the lion was eating before.”

Two and a half decades later, thanks to sophisticated ancient DNA analysis techniques, their suspicions were confirmed and a team in which Gnoske himself participated was able to collect a sufficient number of microhairs to identify the species to which they belonged. In a work published this Friday in the magazine current biologyThe team determined that the Tsavo “man-eating” lions preyed on at least six species: giraffe, oryx, waterbuck, wildebeest, zebra and, of course, humans.

a unique diet

The authors examined a separate sample of four individual hairs and three hair bundles taken from the lions’ teeth and focused on mitochondrial DNA (mtDNA). In humans and other animals, the mitochondrial genome is inherited from the mother and can be used to trace matrilineal lineage over time. “And because it is much smaller than the nuclear genome, it is easier to reconstruct in potential prey species,” says Aleida D. Fleming, a researcher at the University of Illinois at Urbana-Champaign and first author of the paper.

Our analysis shows that historical Tsavo lions hunted giraffes, humans, oryx, waterbuck, wildebeest and zebras

Alida de Flemingham
, Researcher at the University of Illinois at Urbana-Champaign and first author of the article

Among the most valuable data, scientists were able to confirm that the lions shared the same mitochondrial genome inherited from the mother, which supported early reports that they were siblings, and that their mtDNA was from Kenya or Tanzania. It was also consistent with the original. The team documented that the lions had eaten the meat of at least two giraffes, as well as a zebra that was likely native to the Tsavo region.

The researchers were also surprised to find genetic material from wildebeest, as the nearest wildebeest population in the late 1890s was about 80 kilometers away. “This suggests that Tsavo lions may have traveled further than previously thought, or that wild animals existed in the Tsavo region during that time,” says de Fleming.

On the other hand, the absence of buffalo DNA and the presence of a hair of this animal, identified by the microscope, are very valuable details for scientists, since one of the main hypotheses to explain its attacks on humans is that cattle and The buffalo population in this part was devastated by rinderpest, forcing them to look for alternatives.

Although the purpose of this study is not to determine the reasons why lions eat humans, after so many years of study, Gnoske dares to share some hypotheses. He says, “The rinderpest epidemic in the 1890s certainly affected lions in the Tsavo region, as it decimated the African buffalo, which was the main prey of lions in that region.” “The broken teeth theory is actually not what we once theorized. Same injuries as before man-eater They didn’t actually affect or limit their diet or hunting ability. “In fact, the species found in its teeth, in diversity, exceed everything we currently know about an individual lion.”

Responsible science and ethics

Regarding the human DNA found in the samples, the authors have identified a hair from an individual, but declined to describe or analyze it for the current study for ethical reasons. “First, the data analysis traces only one of this individual’s multiple paternal lines (the direct maternal line),” the lead author notes. “Second, to ensure that there may still be descendants in the field today, and to practice responsible science, we are using community-based methods to expand the humanitarian aspects of the project.” Anthropological methods require discussion with local institutions and groups about the project, as well as reporting on the detailed human colonial history of this geographic area, which is beyond the scope of this current study, he emphasizes. Are.

This method could potentially be used on hair from broken teeth of ancient carnivorans from hundreds or thousands of years ago. This method opens a new path of research into the past

Ripon Malhi
, Study co-author and research group leader

Overall, the authors are excited to expand this method to further analyze the different layers of dense hair in dental cavities and apply it in future studies. “You can think of layers in the same way that geologists think of soil layers, where the deeper layers represent historical time and the surface layers are from present-day soil deposits,” explains Dee Fleming. “Similarly, the lower layers in the lower parts of the dental cavity represent prey eaten in the past and the layers at the top of the cavity represent prey eaten more recently.”

In the researchers’ opinion, this type of analysis could provide information about the conflict between humans and lions that still affects many communities in the region and in Africa in general. They summarize, “Our results provide information about the ecology and diet of lions in the past, as well as the impacts of colonization on life and land in this region.” Ripon MalhiWho is the head of the research group. He and his team are convinced that the flaky hairs can allow them to go back in time to recreate the diets of lions of different ages. They concluded, “This method could potentially be used on hair from broken teeth of older carnivores from hundreds or thousands of years ago.” “This method opens up a new avenue of research into the past.”

“A technical achievement”

Geneticist Carles Lalueza-Fox, an expert in ancient DNA and director of the Museum of Natural Sciences of Barcelona, ​​​​believes that this work is an extremely original application of a subject that seems hypothetical but actually happened. “This work has been prepared within a new scientific field which I have called Museomics“, he explains to elDiario.es. “This area involves the recovery of genetic material from museum specimens, which provides historical information about species in the natural world, but in this case, also about their prey,” he summarizes. “To me it seems like a technical achievement; The hairs are small and complex specimens, even though they are over 100 years old.’

This sounds like a technical achievement to me; The hairs are small and intricately patterned, even though they are over 100 years old.

Carles Lalueza-Fox
, Expert in ancient DNA and director of the Natural Sciences Museum of Barcelona

Regarding the ethical concerns of the team analyzing human DNA, Lalueza-Fox believes that it is necessary to be more careful with the potential ethical implications in this area, but she believes that, if they do not identify individual “They could have looked at the population to which they belonged and I don’t think they could have reached lower than East Africa to trace their place of origin,” he says. ” “And that would have been fairly common information.”