These 19th century lions from Kenya ate humans, DNA collected from hairs in their teeth shows

Cell Press

Tsavo lion teeth — image:
The lions’ teeth had been damaged during their lifetimes. Study coauthor Thomas Gnoske found thousands of hairs embedded in the exposed cavities of the broken teeth.
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Credit: Field Museum of Natural History in Chicago

By isolating and sequencing DNA in compacted hairs collected from the teeth of two Tsavo lion museum specimens from the 1890s, researchers have found that the historic lions from Kenya preyed on a variety of species, including humans, giraffes, and wildebeests. These so-called “Tsavo Man-Eaters” are estimated to have killed at least dozens of people, including those working along the Kenya-Uganda Railway in the late 1890’s. The findings appear in the Cell Press journal Current Biology on October 11.

“As biotechnologies advance, there are unexpected sources of knowledge, in this case genomics, that can be used to inform about the past,” says Ripan Malhi (@MalhiRipan) of the University of Illinois Urbana-Champaign. “Our results inform on the ecology and diet of lions in the past as well as on the impacts of colonization on life and land in this region of Africa.”

“A key part of this study was to create a method to extract and analyze DNA from single hairs of prey species found in the teeth of historical museum specimens,” says Alida de Flamingh (@adeflamingh), also at the University of Illinois Urbana-Champaign. “Our analysis showed that the historic Tsavo lions preyed on giraffe, human, oryx, waterbuck, wildebeest, and zebra, and we also identified hairs that originated from lions. This method can be used in many ways, and we hope other researchers will apply it to study prey DNA from other animal skulls and teeth.”

Study co-author Tom Gnoske at the Field Museum of Natural History in Chicago was the first to consider reconstructing the diet of these historic lions using prey hairs from their skulls, the researchers say. With collaborators in Kenya, he began to identify the hairs using microscopy. While conducting ancient DNA research on other animals at the Field Museum, the University of Illinois team got the idea to add genomics as a complementary approach to the study of those compacted hairs.

The Tsavo lions in the new study had dental injuries, including partially broken canine teeth exposing cavities where hair from their prey built up over time. From those tooth cavities, the researchers extracted DNA from individual hair shafts and tiny clumps of hair fragments. While the DNA in those samples was degraded in ways that are typical for historic or ancient DNA, they were able to piece enough of it back together in some of the samples to identify the species the hair originated from. They ultimately identified six prey species, including giraffe, human, oryx, waterbuck, wildebeest, and zebra.

The DNA data narrowed the giraffe sample down to a subspecies of Masai giraffe from southeast Kenya. The researchers also found Tsavo lion DNA that most closely matched other East African lions from Kenya and Tanzania. The researchers said they were most surprised to find hair from wildebeest, noting that it raises questions about their distribution in the past.

“It suggests that the Tsavo lions may have either traveled farther than previously believed, or that wildebeest were present in the Tsavo region during that time,” de Flamingh said. “The closest grazing area for wildebeest was over 50 miles from where the lions were killed in 1898 at the Tsavo-Athi confluence.”

The researchers say they are excited to explore the findings in even greater detail. For example, they suggest that the layered hairs can allow them to go back in time to reconstruct the lions’ diet at different ages. They suggest that such analysis may offer insight into human-lion conflicts that continue to impact communities in Africa, where lions may prey on wildlife as well as domestic animals and humans. The method also holds promise for studies of even older specimens.

“This methodology can potentially be used on hairs from broken teeth of more ancient carnivores from hundreds to thousands of years ago,” Malhi said. “The method opens up a new avenue of inquiry into the past.”

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This work was supported by the US Department of Agriculture, USAID, and the University of Illinois Urbana-Champaign.

Current Biology, de Flamingh et al. “Compacted hair in broken teeth reveal dietary prey of historic lions” https://cell.com/current-biology/fulltext/S0960-9822(24)01240-5

Current Biology (@CurrentBiology), published by Cell Press, is a bimonthly journal that features papers across all areas of biology. Current Biology strives to foster communication across fields of biology, both by publishing important findings of general interest and through highly accessible front matter for non-specialists. Visit http://www.cell.com/current-biology. To receive Cell Press media alerts, contact press@cell.com.

Journal

Current Biology

DOI

10.1016/j.cub.2024.09.029

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Compacted hair in broken teeth reveal dietary prey of historic lions

Article Publication Date

11-Oct-2024

Genomic study identifies human, animal hair in ‘man-eater’ lions’ teeth

University of Illinois at Urbana-Champaign, News Bureau

Lion Eyes — image:
A new study analyzed hairs embedded in the damaged teeth of two “man-eater” lions that killed at least 28 people in 1898 in the Tsavo region of Kenya.
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Credit: Photo copyright Michael Jeffords and Susan Post

CHAMPAIGN, Ill. — In 1898, two male lions terrorized an encampment of bridge builders on the Tsavo River in Kenya. The lions, which were massive and maneless, crept into the camp at night, raided the tents and dragged off their victims. The infamous Tsavo “man-eaters” killed at least 28 people before Lt. Col. John Henry Patterson, the civil engineer on the project, shot them dead. Patterson sold the lions’ remains to the Field Museum of Natural History in Chicago in 1925.

In a new study, Field Museum researchers collaborated with scientists at the University of Illinois Urbana-Champaign on an in-depth analysis of hairs carefully extracted from the lions’ broken teeth. The study used microscopy and genomics to identify some of the species the lions consumed. The findings are reported in the journal Current Biology.

The original discovery of the hairs occurred in the early 1990s, when Thomas Gnoske, a collections manager at the Field Museum, found the lions’ skulls in storage and examined them for signs of what they had consumed. He was the first to determine that they were fully grown older adult males — despite being maneless. He also was the first to notice that thousands of broken and compacted hairs had accumulated in exposed cavities in the lions’ damaged teeth during their lifetimes.

In 2001, Gnoske and Julian Kerbis Peterhans, a professor at Roosevelt University and Field Museum adjunct curator, first reported on the damaged condition of the teeth — which they hypothesized may have contributed to the lions’ predation of humans — and the presence of hairs embedded in broken and partially healed teeth. A preliminary analysis of some of the hairs suggested that they were from eland, impala, oryx, porcupine, warthog and zebra.

In the new study, Gnoske and Peterhans facilitated a new examination of some of the hairs. Co-authors Ogeto Mwebi, a senior research scientist at the National Museums of Kenya; and Nduhiu Gitahi, a researcher at the University of Nairobi, conducted the microscopic analysis of the hairs. U. of I. postdoctoral researcher Alida de Flamingh led a genomic investigation of the hairs with U. of I. anthropology professor Ripan S. Malhi. They focused on a separate sample of four individual hairs and three clumps of hairs extracted from the lions’ teeth.

Malhi, de Flamingh and their colleagues are developing new techniques to learn about the past by sequencing and analyzing ancient DNA preserved in biological artifacts. Their work in partnership with Indigenous communities has yielded numerous insights into human migration and the pre- and postcolonial history of the Americas. They have helped develop tools for determining the species and geographic origins of present-day and ancient tusks of African elephants. They have advanced efforts to isolate and sequence DNA from museum specimens and have traced the migration and genomic history of dogs in the Americas.

In the current work, de Flamingh first looked for, and found, familiar hallmarks of age-related degradation in what remained of the nuclear DNA in the hairs from the lions’ teeth.

“To establish the authenticity of the sample we’re analyzing, we look to see whether the DNA has these patterns that are typically found in ancient DNA,” she said.

Once the samples were authenticated, de Flamingh focused on mitochondrial DNA. In humans and other animals, the mitochondrial genome is inherited from the mother and can be used to trace matrilineal lineages through time.

There are several advantages to focusing on mtDNA in hair, the researchers said. Previous studies have found that hair structure preserves mtDNA and protects it from external contamination. MtDNA also is much more abundant than nuclear DNA in cells.

“And because the mitochondrial genome is much smaller than the nuclear genome, it’s easier to reconstruct in potential prey species,” de Flamingh said.

The team built a database of mtDNA profiles of potential prey species. This reference database was compared with mtDNA profiles obtained from the hairs. The researchers took into account the species suggested in the earlier analysis and those known to be present in Tsavo at the time the lions were alive.

The researchers also developed methods for extracting and analyzing the mtDNA from the hair fragments.

“We were even able to get DNA from fragments that were shorter than the nail on your pinky finger,” de Flamingh said.

“Traditionally, when people want to get DNA from hairs, they’ll focus on the follicle, which is going to have a lot of nuclear DNA in it,” Malhi said. “But these were fragments of hair shafts that were more than 100 years old.”

The effort yielded a treasure trove of information.

“Analysis of hair DNA identified giraffe, human, oryx, waterbuck, wildebeest and zebra as prey, and also identified hairs that originated from lions,” the researchers reported.

The lions were found to share the same maternally inherited mitochondrial genome, supporting early reports theorizing that they were siblings. Their mtDNA also was consistent with an origin in Kenya or Tanzania.

The team found that the lions had consumed at least two giraffes, along with a zebra that likely originated in the Tsavo region.

The discovery of wildebeest mtDNA was surprising because the nearest population of wildebeests in the late 1890s was about 50 miles away, the researchers said. Historical reports, however, noted that the lions left the Tsavo region for about six months before resuming their rampage on the bridge-builders’ camp.

The absence of buffalo DNA and the presence of only a single buffalo hair — identified using microscopy — was surprising, de Flamingh said. “We know from what lions in Tsavo eat today that buffalo is the preferred prey,” she said.

“Colonel Patterson kept a handwritten field journal during his time at Tsavo,” Kerbis Peterhans said. “But he never recorded seeing buffalo or indigenous cattle in his journal.”

At the time, the cattle and buffalo populations in this part of Africa were devastated by rinderpest, a highly contagious viral disease brought to Africa from India by the early 1880s, Kerbis Peterhans said.

“It all but wiped out cattle and their wild relatives, including cape buffalo,” he said.

The mitogenome of the human hair has a broad geographic distribution and the scientists declined to describe or analyze it further for the current study.

“There may be descendants still in the region today and to practice responsible and ethical science, we are using community-based methods to extend the human aspects of the larger project,” they wrote.

The new findings are an important expansion of the kinds of data that can be extracted from skulls and hairs from the past, the researchers said.

“Now we know that we can reconstruct complete mitochondrial genomes from single hair fragments from lions that are more than 100 years old,” de Flamingh said.

There were thousands of hairs embedded in the lions’ teeth, compacted over a period of years, the researchers said. Further analyses will allow the scientists to at least partially reconstruct the lions’ diet over time and perhaps pinpoint when their habit of preying on humans began.

Malhi also is an affiliate of the Carl R. Woese Institute for Genomic Biology at the U. of I.

The National Science Foundation and U.S. Department of Agriculture supported this research.

A genomic study of the maneless Tsavo lions confirmed that they were likely siblings. Pictured: a pair of maneless lions living today in the Tsavo region.

The lions’ teeth were damaged during their lifetimes. Study co-author Thomas Gnoske found thousands of hairs embedded in the exposed cavities of the broken teeth.

Credit

Photo Z94320 courtesy Field Museum of Natural History in Chicago

Hairs embedded in the lions’ teeth included those of zebra, top, and wildebeest, bottom.

The study also identified hairs from two giraffes in the lions’ teeth.

Credit

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In the 1990s, a team from the Kenya Wildlife Service and the Field Museum of Natural History in Chicago found a cave that the “man-eater” lions had used in Tsavo, Kenya. The team included Thomas Gnoske, front row, far left; Julian Kerbis Peterhans, front row, far right; and Samuel Andanje, back row, second from left, a KWS research biologist who, with Gnoske and Kerbis Peterhans, coordinated the search for the cave.

Credit

Editor’s notes:

The paper “Compacted hair in broken teeth reveal dietary prey of historic lions” is available online or from the U. of I. News Bureau.

Michael Jeffords and Susan Post are wildlife photographers, authors and research affiliates of the Illinois Natural History Survey at the Prairie Research Institute of the U. of I. Their photographs are available here