Scientific detectives take up the search for an infamous "lions' den," lost for one hundred years.
One of the most popular displays at Chicago's Field Museum of Natural History is a diorama with two maneating lions. These are the mounted skins of a pair of male lions that, one hundred years ago, went on a twelve-month rampage in southern Kenya, killing at least 128 people, many of them employed in building a railroad line into the interior of the country. Work on the railway was halted until the marauders were finally tracked down and shot by J. H. Patterson, a British engineer directing construction of a bridge for the railroad. Not long afterward, Patterson stumbled upon a "fearsome-looking" cave. In his 1907 memoir, The Man-Eaters of Tsavo and Other East African Adventures, he recalls this incident: "Round the entrance and inside the cavern I was thunderstruck to find a number of human bones, with here and there a copper bangle such as the natives wear. Beyond all doubt, the man-eaters' den." Patterson even took a photograph of the cave entrance, but unfortunately, the location of this notorious lions' den, somewhere in the west section of what is now Tsavo National Park, was soon forgotten.
As members of the Field Museum staff, familiar with the diorama and Patterson's memoir, some of us became intrigued by his description of the supposed lions' lair, which to a naturalist sounds much more like a hyena den. Although the maneaters had been observed dragging off some of their human victims and, conceivably, could have returned to a home cave in order to feed, such behavior has not been documented in the modern lion species. Lions consume most of their prey near the kill site. Hyenas, however, do have dens to which they retreat with marrow-bearing bones. Perhaps the human remains Patterson saw were left by hyenas that had scavenged the man-eaters' prey.
Six years ago, we began to entertain the notion of locating the cave. We felt that if we could analyze the skeletal contents, this lion-versus-hyena question could be resolved. Analysis of the bones and artifacts could also confirm whether or not they had been amassed during the man-eaters' reign of terror; if so, we should find some remains of Indian laborers, who were among the victims.
A search for the cave could also prove useful for students of early human evolution. When paleontologists find fossil bones of our ancestors, they want to know how the remains got to be where they are. While we commonly think of our forebears as hunters, they could just as often have been prey, ending up as a few gnawed bones. A modern carnivore den with human remains-whether it belonged to lions or hyenas-would give paleontologists a good idea of what clues to look for when examining fossil bones.
As for the string of killings in 1898, other questions also interested us. For example, was this due to some aberration in the nature of these specific animals? In the wild, most lions and other large cats avoid contact with people. Wounded or old animals, however, must resort to relatively easy prey, frequently including humans and livestock. One of the maneaters at the Field Museum had a broken lower right canine with an exposed root; asymmetrical growth of the skull in response to this abnormality suggests the beast had suffered from this condition for a long time. Perhaps he was too disabled to hunt and consume the usual prey. We do know that after he was shot, no more humans were killed, although the second lion made several unsuccessful attacks before being shot as well, three weeks later. This suggests that the first lion may have been the main culprit.
Another possibility is that the attacks, which took place along an eighty-mile stretch of railroad located between Voi and Kima, were part of an established pattern. The railway track followed a traditional caravan route from the interior of East Africa to the Mombasa coastal region. …