In 1898, a camp of bridge builders over the Tsavo River in Kenya was met with terror. Reason? Two huge maneless lions decided to turn the camp into their night shelter. This isn’t about a few stray cats. It’s about two fearless, hulking creatures who use darkness as a cloak to attack tents and drag victims away. Tsavo’s notorious man-eating lions are said to have killed at least 28 people before the project’s civil engineer, Lieutenant Colonel John Henry Patterson, put an end to the terror.
But these lions were not forgotten. In 1925, Patterson sold his remains to the Field Museum of Natural History in Chicago. Fast forward to today, and these ruins have become the subject of intriguing research.
Tsavo’s man-eating lions
Recently, researchers from the Field Museum collaborated with scientists from the University of Illinois at Urbana-Champaign to shed light on some previously unstudied aspects of these lions. Experts used microscopy and genomics to identify some of the species consumed by Tsavo cannibals. Findings published in the journal Current Biologyreveals intriguing new details about these maneless predators.
Human hair in lion’s teeth
The initial discovery of feathers began in the early 1990s by Thomas Gnoske, collections manager at the Field Museum. Examining the skulls of lions for signs of their eating habits, Gnoske made some intriguing discoveries. He was the first to conclude that these lions were fully grown adult males, despite their lack of manes. He also found that thousands of broken and stuck hairs accumulated in damaged teeth throughout their lives.
In 2001, Gnoske, together with Julian Kerbis Peterhans, a professor at Roosevelt University and associate curator at the Field Museum, first reported the damaged condition of lion teeth and the presence of bristles embedded in open cavities. Initial analysis suggested that the hairs came from canna, impala, antelope, porcupine, wild boar and zebra.
Fast forward to today, and a recent study has allowed for a more in-depth investigation of hair. The microscopic analysis was carried out by Ogeto Mwebi, Senior Research Fellow, National Museums of Kenya; and researcher Nduhiu Gitahi from the University of Nairobi.
DNA study of lions in Tsavo
Alida de Flaming and Ripan S. Malhi of the University of Illinois at Urbana-Champaign led the hair genomics study. They focused on four individual hairs and three strands extracted from the lion’s teeth. The study found familiar signs of age-related degradation in nuclear DNA residues in lion teeth. After identification, de Flaming focused his attention on mitochondrial DNA (mtDNA).
This type of DNA is inherited from the mother and can be used to trace ancestors back into the past. So why focus on mtDNA? First, it is more abundant in cells than nuclear DNA and is easier to reconstruct in potential prey species.
Tsavo’s man-eating lion DNA
The researchers created a database of mtDNA profiles of potential prey species and compared them with mtDNA profiles obtained from hairs.
“We even managed to get DNA from fragments shorter than your little finger nail,” de Flaming said. “Traditionally, when people want to extract DNA from hair, they focus on the follicle, which contains a lot of nuclear DNA,” Malhi said. “But these were fragments of hair strands that were more than 100 years old.”
Leo’s food preferences have been revealed
DNA analysis of the hair revealed that giraffe, human, wildebeest, waterbuck, antelope and zebra were prey. Interestingly, there were also hairs from other lions. Evidence suggests the lions were siblings and likely ate at least two giraffes from the Tsavo area in addition to the zebra.
Surprisingly, even wildebeest mtDNA was present. This was unexpected since the nearest antelope population in the late 1890s was approximately 50 miles away. Conversely, the absence of buffalo DNA and the presence of only a single buffalo hair was also surprising. Today buffalos are the favorite prey of lions in Tsavo.
The connection of history and science
Perhaps the most poignant part of this story is its connection to the past. Julian Curbis Peterhans recalled the historical aspect of this investigation; Colonel Patterson’s handwritten field diary while at Tsavo.
There was no mention of buffalo or native cattle in Patterson’s reports, most likely because these populations were decimated by a viral disease called rinderpest that was brought to Africa from India in the early 1880s.
Importance of the study
In addition to fascinating insights into the Tsavo cannibals, this study is a step forward in scientific research. We now know that we can reconstruct entire mitochondrial genomes from individual hair fragments that are more than a hundred years old! Because lions’ teeth fill with thousands of bristles over time, further analysis could help reconstruct their feeding patterns over time and perhaps pinpoint when they began preying on humans.
The research, supported by the National Science Foundation and the U.S. Department of Agriculture, is also a testament to advances in biotechnology.
Unexpected sources of information
“As biotechnology advances, unexpected sources of information (in this case genomics) emerge that can be used to obtain information about the past,” said Ripan Malhi.
“Our results provide insight into the ecology and diet of lions in the past, as well as the impact of colonization on life and land in this part of Africa.”
Thanks to the methodology developed in this study, the possibility of extracting DNA from bristles in the broken teeth of older carnivores dating back hundreds or thousands of years is now a reality. The study was published in the journal Current Biology.
Source: Port Altele
