Lt. Col. John Henry Patterson, a British civil engineer overseeing construction of a railway bridge over the Tsavo River in Kenya, shot and killed both Tsavo man-eating lions in late 1898. Patterson was not a professional hunter. He was the project leader responsible for keeping construction on schedule, and the lions had brought work to a complete standstill.
Why Patterson Had to Act
In 1898, the British were building the Uganda Railway across East Africa, a project so plagued by disease, hostile terrain, and dangerous wildlife that it earned the nickname “the Lunatic Line.” When crews reached the Tsavo River and began constructing a bridge, two male lions began dragging workers from their tents at night. The attacks were relentless. Crews tried fires, thorn fences, and noise to scare the lions away, but nothing worked. Workers fled the area by the hundreds, and bridge construction ground to a halt. Patterson, as the senior engineer on site, decided to hunt the lions himself.
He killed the first lion on December 9, 1898, and the second on December 29. The attacks on humans and livestock stopped immediately. The railroad was completed a few months later.
How Many People the Lions Killed
Patterson claimed the lions killed 135 workers, a number that became legendary but is almost certainly inflated. Modern estimates vary widely, from 28 to 135 victims. In 2009, researchers at the University of California, Santa Cruz analyzed the chemical signatures preserved in the lions’ bones and hair to determine how much of their diet had been human. Their findings suggested the lions’ reliance on human prey was significant but concentrated in the final months of the attacks, with one lion consuming considerably more people than the other. The total likely falls well below Patterson’s dramatic figure, but even the lower estimates represent an extraordinary level of predation on humans.
Why These Lions Targeted People
Several factors converged to make the Tsavo lions unusually dangerous. The most important was a collapse in their natural food supply. In the 1890s, a devastating cattle plague called rinderpest swept across Africa, wiping out cattle and buffalo populations. Buffalo were the primary prey of Tsavo lions. With their main food source decimated, the lions had fewer options, and a massive construction camp full of workers sleeping in tents presented an easy alternative.
Dental disease likely played a role too. Examination of the first lion’s skull revealed a broken lower canine that had developed a severe abscess, along with three missing lower incisors, possibly knocked out by the kick of a struggling prey animal. The bone around the injury had remodeled extensively, meaning the lion had been living with this damage for years. Hunting and killing large, powerful animals like buffalo requires a fully functional set of teeth. A lion with a painful, infected jaw would naturally gravitate toward prey that was easier to subdue. The second lion had a fractured tooth as well, though less severe.
The construction site itself was also uniquely vulnerable. Workers camped in the open near the river, in the middle of thick thornbrush that provided perfect cover for stalking predators. The combination of desperate, injured lions and an exposed human population created the conditions for one of history’s most notorious episodes of animal attacks on people.
The Maneless Lions of Tsavo
One detail that makes the Tsavo lions instantly recognizable is that neither had a mane. Male lions across most of Africa sport large manes, but Tsavo males are consistently maneless or nearly so. Researchers have proposed several explanations, but the most widely accepted is environmental: the Tsavo region is blisteringly hot, arid, and covered in dense thornbrush. Growing and maintaining a thick mane in that habitat costs more than it’s worth. The extra insulation causes overheating, the long hair snags on thorns, and the conspicuousness makes hunting harder. Some researchers have also noted that Tsavo males may have elevated testosterone levels, which could paradoxically contribute to both hair loss and their reputation for unusual aggression.
What DNA From Their Teeth Revealed
More than a century after Patterson’s hunt, the lions are still yielding new information. In 2024, researchers extracted and analyzed DNA from tiny fragments of hair that had become compacted in the cracks of the lions’ broken teeth over years of feeding. The results painted a detailed picture of what the lions had been eating: giraffe, human, oryx, waterbuck, wildebeest, and zebra. Some of the hair even came from lion itself, suggesting the animals had groomed or fed on other lions.
The giraffe DNA was specific enough to identify the prey as belonging to a subspecies of Masai giraffe typically found in southeastern Kenya, confirming the lions’ geographic range. The lion DNA recovered from one hair sample matched the genetic profile of the Tsavo lion it was lodged in, consistent with self-grooming. These findings confirmed that while the lions were eating humans, people were just one component of a varied diet that still included wild prey when available.
Where the Lions Are Now
After killing the lions, Patterson kept their skins as floor rugs for roughly 25 years. He eventually sold them to the Field Museum of Natural History in Chicago, where taxidermists mounted them as full-body displays. Both lions remain on exhibit there today, slightly smaller than they would have appeared in life because the skins had shrunk and worn thin after decades of use as rugs. Their skulls are also held in the museum’s collection and have been the basis for most of the scientific studies conducted on the pair over the past century.