The Man-Eating Lions of Tsavo are without a doubt, two of the most famous specimens on display at The Field Museum, thanks in part to the 1996 film 'The Ghost And The Darkness'.

But the movie isn't without its flaws and inaccuracies: for instance, it was filmed in South Africa instead of Kenya, and the lions in the film have gorgeous manes and were from a zoo in Ontario - but, the drama is based off of true events. The tale went like this: In 1898 a duo of lions began attacking and consuming railway workers in Tsavo, Kenya.

Their story was immortalized by colonel John H. Patterson's first hand account in his book: THE MAN-EATERS OF TSAVO AND OTHER EAST AFRICAN ADVENTURES Patterson was a civil engineer and was assigned the task of completing a bridge for the Kenya-Uganda railway, but a week after his arrival, a pair of male lions began dragging men out of their tents in the middle of the night their screams filling the air. First estimates for how many people were attacked, ranged between 28 and 135 men over the period of 9 months before Patterson was able to finally shoot and kill the pair within a few week of one another.

He turned them into living room rugs and they existed as such until, while passing through Chicago in 1925, he sold them to The Field Museum, and we promptly turned them into the taxidermy mounts you can still see on display today. In 2009, a hundred and eleven years after they were killed, scientists were able to examine hairs from their pelts looking specifically at bone collagen and hair keratin values. The levels of these values reflect the sort of things the lions have been eating in the last years and months of their lives.

Because grazers, like antelope, leave different levels than carnivorous humans. Those results estimate that, together, the two lions consumed about 35 people A hundred less than colonel Patterson's estimates, but still, 35 individual human beings. That all being said, there's still a bit of an unanswered question: why did they do it?

The theories range from food scarcity and desperation, or that the lions possibly gained a taste for human flesh after feeding on railway workers who had died of other causes. Another consideration is that one of the lions suffered major dental trauma and had evidence of a serious infection, which could have precluded it from hunting and taking down its typical game. But according to the 2009 research, that lion, the one with the dental damage, had a record of 24 humans consumed meaning its partner in crime consumed at least 11 people too.

Another way of looking at this, is to say human carcasses comprised 30% and 8% of each lion's diet respectively the last 3 months of their lives. So, we decided to go talk with Dr. Bruce Patterson, curator of mammals here at The Field Museum about some of these theories Dr.

Patterson: There's a theory that was developed, actually by a British colonial in India And what he found was that in case after case, these man-eating big cats were almost invariably crippled in some way. And, when an apex predator is unable to pursue its normal prey, often they'll turn to something slower, that sees worse, hears worse and navigates worse in the dark. Now, I'm holding the skull of the first man-eater, and if you look at this part of its jaw, you'll see a broken lower right canine.

Patterson thought that that was the bullet hole, but it's actually the pulp cavity of the tooth where the nerves and blood vessels that nurture the living tooth reside. If you look around the edges of it, you can see that the tooth is actually polished by wear. but we have other evidence in the skull itself that tell us that this injury happened years before the lion's eventual death. The most eloquent testimony to the remodeling of the skull in the wake of this injury, comes from upper right canine You can see on the left side that the upper canine is normally held outside and behind the lower canine. but with this tooth out of its mouth, the upper canine is rotated inward and forward to the point where its tip is resting on the stump of the broken tooth.

It's been said by one British WAG that these lions viewed the arrival of 3000 railway workers in their territory with considerable enthusiasm. [Emily] Yeah, all of a sudden they just had an open buffet. What about this one? I mean these two were working in pair, so if this one wasn't suffering that same kind of, like, dental malady why would this one start consuming humans as well? [Bruce] So, these guys presumably lived together all their lives.

We think this one was guilty by association with this one. Lions usually eat things that eat grass, like zebra, wildebeest and buffalo. and so most lions share the chemical signature of their grass-feeding prey but a man-eating lion will show this anomaly of C3 photosynthesis in its tissues and this lion, not only showed a stronger signature than that, but when we analyzed his hair this one had a huge spike towards man-eating, this one, hardly any at all. [Emily] The nature of science is that each of these ideas needs to be tested, retested and examined and recently, we got to sit down with Dr. Larisa DeSantis from Vanderbilt University Her research focuses on studying extinction events in certain Pleistocene species, like the saber-tooth cats.

She does this by examining dental wear patterns, called Microwear, in animals like hyenas and lions. Hyenas eat a lot of bones compared to African lions, which leaves certain obvious wear patterns on their teeth But by noticing and studying changes in micro-wear patterns of an African lion's teeth, it can mean big changes in their available diet. She was curious: if the Tsavo lions were desperate enough to consume even the human bones, then it could indicate that a lack of their typical prey is what drove them to turn to humans. [Larisa] So, one of the things we try to do is understand the ecology of these animals but obviously we can't observe what they were doing in the past. so we can use clues from both today and from the specimens themselves and one of the things we can do is study their teeth.

The micro-wear, essentially, will capture the diet of the animal over the past few days to weeks of its life so we can get some idea of it, whether it was sort of eating lots of flesh or more generalized like lions are today or if it was, sort of, concentrating on eating lots of bones, much like hyenas. Before we can do all of this, we actually have to study the modern mammals alive that we can observe and we know what they're doing. Correlate that known feeding behaviour, we can use that as sort of a modern baseline to then going back into the past to assess what ancient animals were doing so then we can look back and see were times really tough at the end of the Pleistocene before the animals went extinct?

Were humans, sort of competing with a lot of these carnivores for prey resources? Were they desperately consuming carcasses before they went extinct? so we can actually test some of those ideas and overturn some of those ideas, in fact. But in this case, we're really fascinated by the Tsavo Lions because they had a notable difference in their diet which was [Emily]They were-- people.. they're people-eating. lions. [Larisa] Exactly.

Some of the questions are: why was that? There's some historical accounts of bone crunching and whatnot So, was it that they were, sort of, desperate? It could've been drought events that were happening and reduction in the prey base [Emily] Can you walk us through how you get one of these impressions? [Larisa] Sure.

So, the first thing we have to do is we have to clean the teeth. We let them dry and then we use this dental impression material, which will mix and form a mold and then we wait for that to harden, then we remove the mold [Emily] This is actually what a dentist would use. When you contact the dental supply company, do you say: 'Hi, I'm a paleontologist or I'm a zoologist and I wanna get some impressions of a man eating lion?' Do you think they hear that very often? [Larisa] So, I usually don't tell them, but I do tell my dentist and he thinks it's pretty funny. and then when we get back to Vanderbilt, we will actually take a little bit of putty and wrap it around the mold itself, so that we can pour epoxy in.

And the epoxy is able to capture all of the fine details of the tooth itself so it's an exact replica of the tooth and so we can actually look at a 100x magnification, even higher, and capture all of the details [Emily] Wow! [Larisa] And quantify that in three dimensions. [Emily] So, we're not actually going to know today, the answer to this burning question? [Larisa] No, it's gonna take a little while. It's always the most fun part of the job: is when you actually figure out what they were, what they were eating or how they were behaving. [Emily] Yeah [Larisa] Either in 1898 or millions of years ago. [Emily] So Larisa's got a little bit of work to do back in her lab, but here's the point we're trying to get across: These lions have been dead for over a century, yet with new technologies and creative interpretations we're able to pursue questions about what motivated their actions in the final months of their lives Bruce says it better. [Bruce] You know it's astonishing that 117 years after their death, we can be talking about, not only how many people they ate, but differences in the behaviour of two animals, all from a skin and a skull in a museum collection and when you think of the hundreds of thousands of specimens downstairs and all the stories they have to tell that we're short of man-power and time to develop [Emily] Yeah. [Bruce] The value of museum collections is just astronomical [Brain Scoop Theme] The Brain Scoop is made possible by The Field Museum and The Harris Family Foundation Larisa DeSantis' research is supported by The National Science Foundation ... It still has brains on it