Lions In Famed Killings Get Partial Reprieve

ROBERT SIEGEL, host:

The two Tsavo lions were man-eating cats that, according to John H. Patterson, ate 135 people who were building a railroad in Kenya in the late 1890s. Patterson was the British engineer who shot the lions. That incident inspired the 1996 movie, �The Ghost and the Darkness,� in which Val Kilmer played Patterson.

(Soundbite of movie, �The Ghost and the Darkness�)

Mr. VAL KILMER (Actor): (As Colonel John Henry Patterson) Everything is collapsing on me. Every morning, the ground is soaked with blood. The workers feel I brought this terror since it didn't begin till my arrival. Whatever I try, they seem to know. All the deaths are on me.

SIEGEL: Well, after their man-eating days were done, the lions were stuffed and put on display at the Field Museum in Chicago where much was made of those 135 human meals. Now, a new report says the lions might not have been quite so blood thirsty as originally thought. Justin Yeakel of the University of California, Santa Cruz, is one of the researchers who wrote the report. And I asked him based on his research, how many people the Tsavo lions actually ate.

Mr. JUSTIN YEAKEL (Researcher, University of California, Santa Cruz): We put the most likely estimate to be about 35, but it could also range between four and 72. Those values are just not as likely as 35.

SIEGEL: Now, how on earth do you measure the number of humans consumed by two stuffed lions more than a century later?

Mr. YEAKEL: Well, we used a analytical tool. Basically, we utilize the chemical signatures and their bone and hair to work back their most likely sources for those chemical signatures. Specifically, we were looking at ratios of stable isotopes which are unique among different kinds of animals and they're retained in consumers of those animals. So, if you think of each prey as a different color of paint, the predator would be mixing the paint in a certain way. And so, we were calculating the most likely contribution of each color to make that particular mix of paint that we were seeing in the two man-eating lions.

SIGEL: And your conclusion is there wasn't so much representation of the human color as to justify the 135-kills number.

Mr. YEAKEL: Right, and this is where things get interesting because not only did we think that, well, perhaps they weren't consuming as many humans as they reportedly did, but also perhaps the two lions had very different diets according to our analysis. So, only one of the two lions was gaining any significant nutritional benefit from humans, the other was obtaining its food elsewhere.

SIEGEL: Now, I read that the period of supposedly eating 135 railway workers took place over a period of nine months. If indeed the lions had only taken up eating railway workers very recently would their hair have disclosed that? What if it been just something that they'd started doing late in life?

Mr. YEAKEL: We were taking advantage of the fact that different biological tissues incorporate dietary information at different rates and over different periods of time. So, we analyzed both bone and hair tissues from the lions. Hair gives you a dietary window of about three months of so, whereas because bone turns over at a much slower rate, you can get a much longer time window. And so we estimate that to be at about six years. And since the lions are only supposed to be about seven or eight years old based on their dental records, their bone values are basically a lifetime average.

The bone values and hair values were not the same. So, when you look at the isotopic values of their hair, for one lion they moved towards relying on human prey to a much higher degree. And we estimate that to be at around 30 percent.

SIEGEL: So, now you and your colleagues have to write the revised screenplay for �The Ghost and the Darkness� to get the number of kills down to�

(Soundbite of laughter)

SIEGEL: �down to scientific reality.

Mr. YEAKEL: I don't know. I think it'd be hard to bit 135 in terms of telling a scary story. So, I think we might not be competitive on that front if we took the number 135 and changed it to 35.

SIEGEL: Well, Justin Yeakel, thank you very much for talking with us today.

Mr. YEAKEL: It's been a pleasure, thank you.

SIEGEL: Justin Yeakel of the University of California, Santa Cruz. He's one of the researchers who rewrote the story of the Tsavo man-eating lions. Transcript provided by NPR, Copyright National Public Radio.