126 years ago, two lions hunted a bridge crew, revealing a gruesome diet

A recent study has shed new light on the dietary habits of the infamous Tsavo "Man-Eaters" lions through DNA analysis of hairs found in their teeth. Researchers from the University of Illinois Urbana-Champaign, led by postdoctoral research fellow Alida de Flamingh, identified the prey of these notorious lions by extracting and sequencing DNA from hair fragments preserved in their broken teeth, according to reports from Popular Science and Science Daily.

The lions became known as the "Man-Eaters of Tsavo" for their attacks on railway workers in 1898 during the construction of a bridge over the Tsavo River in Kenya. The attacks resulted in the deaths of at least 28 people over a span of about nine months, with some estimates of the final death toll ranging as high as 135.

Lieutenant-Colonel John Henry Patterson, the engineer in charge of the railway project, eventually hunted and killed the two lions after a difficult hunt that became world-famous. The lions were so emboldened that they often dragged workers from their tents at night to eat them, leading to a complete halt in railroad construction, according to The New York Times. In 1924, Patterson sold the remains of the lions to the Field Museum of Natural History in Chicago, where they have been on exhibition since 1925.

The researchers focused on mitochondrial DNA (mtDNA), which is inherited maternally and provides abundant genetic information that is relatively easy to reconstruct in potential prey species. "We were even able to get DNA from fragments that were shorter than the nail on your pinky finger," said de Flamingh, as reported by Science Daily. The researchers developed an innovative method to extract and analyze DNA from the hair shafts, a technique that can be applied to other ancient specimens.

Their findings revealed that the lions' diet included humans, giraffes, wildebeests, zebras, oryx, and waterbuck. Using recent advances in sequencing and analyzing old and degraded DNA, the researchers identified hair from six different prey species, as stated by Science News. The discovery of wildebeest DNA was particularly surprising, as wildebeest populations were located about 80 kilometers away from Tsavo in the 1890s. "This indicates that the Tsavo lions may have traveled farther than previously thought," de Flamingh said, according to Science News.

The study also found lion mtDNA in the hair samples, suggesting close social behavior between the two lions. "Lion hair trapped in their teeth suggests that the brothers were closely bonded and groomed one another," said Julian Kerbis Peterhans, a professor at Roosevelt University and the Field Museum, as reported by UOL.

The researchers opted not to conduct further analysis of the human hairs to identify potential victims. "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," the researchers stated, according to Popular Science.

The study also provides evidence that dental injuries in the lions may have influenced their unusual predatory behavior. An analysis of the lions' jaws revealed they likely suffered from painful dental injuries while alive, making it difficult for them to hunt and eat large prey, thus making humans easier targets, as stated by Science Daily.

Advances in microscopy and genomics have allowed researchers to reconstruct the diet and environment of the Tsavo lions. "You no longer need a follicle cell on a hair to extract and read the DNA," said Ripan S. Malhi, an anthropological geneticist at the University of Illinois Urbana-Champaign, as reported by Nature.

The research was published in the scientific journal Current Biology. The National Science Foundation and U.S. Department of Agriculture supported this research.

Popular Science, The New York Times, Nature, and The Wall Street Journal reported on the findings, among others.

The article was written with the assistance of a news analysis system.