Ghosts of Tsavo Read online

  For the next several years, Kerbis Peterhans and Gnoske commuted between Chicago and Africa. They rediscovered the false man-eaters’ den in Tsavo and the apparently real den in the Kyambura Gorge. Their research also took them to museums in Europe, Africa, and North America to study the skins, skulls, and skeletons of modern and extinct lions, the purpose of which was to test the validity of Gnoske’s visual impressions that certain lions had atypically small heads and big bodies.

  “Tom has this great artist’s eye,” Kerbis Peterhans said. “He can look at a fossil skull in a London museum and then a recent skull in Nairobi and see that they’re the same. Most people wouldn’t notice that. But then you have to take careful measurements to confirm the impression.”

  There are few complete lion skeletons in the world’s museums and they are hard to find. The two men had examined ten so far, and they said that what they found tended to support their hypothesis of two distinct types of lions living side by side in Africa.

  It was show-and-tell time. We returned to Gnoske’s office, where he produced two boxes and pulled a lion’s skull from each and laid them side by side on his desk. The first was from a mature plains lion, and it was obviously larger than the second, which came from a mature “buffalo lion,” the nickname the two researchers gave to the second type because it preys predominantly on buffalo. They used the term interchangeably with “Nile River lion,” having observed the animal most often in river valleys, or near lakeshores—habitats where buffalo congregated.

  The skull of the classic plains lion, said Gnoske, averages fifteen inches long by ten inches wide, and weighs five pounds dry; buffalo lion skulls average thirteen by eight inches and weigh three and a half pounds dry. There are other differences. The spheno-palatine foramen, an opening through which a nasal artery passes, is bigger in plains lions than in buffalo lions. The former also have a deeper sagittal crest, a kind of ridge atop the skull to which the upper jaw muscles attach, and a more developed pterygoid process of the lower mandible, to which the lower jaw muscles are fixed.

  Moving lower in a lion’s anatomy, a flange on the shoulder bones, called the deltoid ridge, is larger in buffalo lions, which, being anywhere from six inches to a foot taller, also have longer and stouter humeri.

  Dizzied by the terminology, I asked, What does it all mean? Gnoske and Kerbis Peterhans took me through it, step by step.

  The spheno-palative foramen: They didn’t know why it was larger in plains lions, but speculated that it accommodates a larger nasal artery, which suggests that those lions have a keener sense of smell. Why? Again, no answer, but possibly because they live in large prides, that is, are more “social.” They need a more acute sense of smell to better locate other lions. But that explanation, the two men stressed, was purest speculation.

  The sagittal crest may be larger in pride lions to support more powerful jaw muscles. Ditto for the lower mandible. Plains lions require much stronger jaws than buffalo lions, not to kill prey (because they do little hunting) but to deliver decisive bites in battles with rivals for control of their prides. Their shorter stature and more compact build give them a lower center of gravity, making them harder to knock off their legs. A plains lion is a warrior, a buffalo lion a hunter. Despite its greater size, the latter would probably lose in a fight with the former. “It would be like a fight between a pit bull and a German shepherd,” Gnoske said by way of illustration. “The pit bull would probably win. A German shepherd is a lot bigger, but a pit bull has a bigger head and stronger jaw muscles relative to its body size.”

  The deltoid ridge would be larger in the buffalo lion because, according to the Gnoske–Kerbis Peterhans scenario, they do most of the hunting—larger deltoid ridges support bigger deltoid muscles, which are necessary to bring down their huge prey. Allen Turner, an African naturalist, had theorized that the deltoid ridge in buffalo-killing specialists becomes even more pronounced over time due to the constant muscle stress of wrestling with the three-quarter-ton bovines.

  Turning from the lion’s skeletal structure to its exterior, the two researchers stated that plains males always develop luxuriant manes at maturity, whereas buffalo lions, which tend to live at lower elevations, grow variable manes, ranging from sparse crests, collars, and side whiskers to manes roughly half the size of their Serengeti cousins’. Abbreviated manes and tail tufts thicker than plains lions’ are features that Asiatic and buffalo lions have in common. They also share a physical peculiarity with tigers—a belly fold: a thick, pendulous flap of skin on their bellies not found in lions on the savanna. Interestingly, the lions in cave paintings, in addition to having restricted manes, are also portrayed with belly folds. The pronounced deltoid ridge in buffalo lions bears some similarities to a flange found on the shoulder bones of extinct cats, like the saber-toothed cat and the prehistoric feline predator with the dire name of Smilodon fatalis, both of which were equipped to kill big prey. One possible explanation for such physical differences—and it was no more than a possibility, Gnoske emphasized—is that buffalo lions and the lions of India’s Gir Forest may represent the “primitive condition” of the lion. That was another way of saying that they are a kind of missing link or living fossil, virtually unchanged from the lions painted on cave walls during the Stone Age.

  Finally, there were differences in behavior and social structure. Lion society on the prey-rich savanna is matriarchal, with females in charge of hunting chores and the males in charge of controlling and defending large prides that are the leonine version of extended families. Along the riverbeds in what field zoologists call the “prey-depauperate” African scrublands, lion society is patriarchal and characterized by smaller prides, ranging from a single breeding pair with cubs to perhaps half a dozen animals—nuclear families. In Tsavo, for example, Gnoske and Kerbis Peterhans observed a solitary bull buffalo warding off repeated attacks by a single male lion for 45 minutes while a female with three adolescent cubs watched from a distance.

  Assuming that there are marked differences between buffalo lions and the lions of the wide-open spaces, what accounts for them? Because the fossil and historical record is sketchy, Gnoske and Kerbis Peterhans can offer only an explanation that is partly factual, partly a scientific folktale.

  The facts: Palaeontologists argue that the unmaned lions depicted in 30,000-year-old cave paintings were 25 percent bigger than modern lions. Gnoske and Kerbis Peterhans argue otherwise: The skeletons of extinct lions they’d studied in museums are virtually identical to those of buffalo or river lions.

  Palaeontologists also assert that the genus Panthera arose millions of years ago in Central Asia. They preyed on wild oxen and cattle, the ancestors of domestic livestock. Environmental changes taking place over a vast span of time, between one million and two million years ago, caused the herds to begin migrating along river systems into western Asia, southern Europe, and eventually into Africa. The great predators followed them, so that, when the world entered historical times, Asiatic lions were established in what is today’s Near East, Greece, the Balkans, and southern France, hence the numerous references to lions in the Bible and other ancient texts. In his Histories, Herodotus mentions that the lions of his era (the fifth century B.C.) preyed on the wild cattle and buffalo that roamed Greece and Turkey.

  Gnoske and Kerbis Peterhans conjecture that the Jordan River depression, joining the Euphrates River to the Nile, created a corridor for primitive lions to invade Africa from Eurasia. Over time, these feline nomads, trailing herds of wild ungulates, established themselves along Africa’s major river systems. During that era, they conjecture further, the social structure of the lion was in all likelihood no different from that of other cats in the genus Panthera (which includes leopards, jaguars, and tigers) : It was a solitary animal, or, at most, lived in quite small family groups, just as leopards, jaguars, and tigers do today. In social terms, that was the primitive condition of the lion.

  At some point in the past, perhaps drawn by the wealth of prey a
nimals, some lion populations emigrated from the river valleys to the African savannas. But they were confronted by a problem: Yes, there was an abundance of prey on the grassland, and it was less dangerous to the predator than wild buffalo, but animals like wildebeest, zebra, and gazelle were also much faster and more nimble. Lions may have developed specialized traits to neutralize that advantage, taking to living in the large, cooperative hunting societies we call prides. Sexual roles changed as lion society underwent a kind of feminist revolution that made plains lions the only social animal among the big cats. Bands of sisters and aunts shared in caring for the young, but also became the primary hunters.

  Any tourist who has spent time in an African national park, or any couch potato addicted to TV nature shows, has seen lionesses venturing out in disciplined hunting parties, executing pincer movements around a zebra or wildebeest herd or making “game drives” in which a couple of females set up an ambush position while three or four more chase prey animals into it. Why did females become the hunters? Killing buffalo requires brute strength and ferocity; seizing hard-to-catch prey on the savanna demands stealth and agility, attributes that lionesses possess to a greater degree than males. They are smaller and more nimble, and they don’t have manes, which make males too obvious to plains prey and also slow them down when in hot pursuit.

  So, with buffalo and other large prey like young elephant and hippo relegated to secondary items on the menu, masculine physical power was no longer so necessary. Having become semi-obsolete as a hunter, the grasslands male evolved into a formidable fighting machine. With females concentrated into tightly knit groups, he couldn’t single out one breeding-age female and, so to speak, carry her off to live in isolated bliss. Marry one and you married her sisters as well, with her mother and aunts thrown into the bargain. Limited access to fertile lionesses caused competition for their attentions to become fierce, so adult males developed massive heads and jaw muscles, shorter, more compact bodies, and luxuriant manes. Meanwhile, back on the river systems, lions morphologically and behaviorally remained the same as they’d been in the Pleistocene era. The Man-eater of Mfuwe, whose stuffed replica was being ogled three floors below, was a classic of the breed: a solitary, maneless rogue with a small head relative to its enormous body.

  And so the conversation briefly turned to the topic that had drawn me to Tsavo in the first place. If the two researchers accomplished nothing else, they hoped to soon solve the century-old mystery of what had caused Ghost and Darkness to become such ravenous consumers of human flesh. They were working on a study structured around several factors that lead to man-eating, factors they’d isolated during their work in Tsavo: the traditional one of injury, sickness, or old-age; decimation of “normal” prey; access to dead or dying human beings; a “social tradition” of man-eating; the role of habitat and vegetation; and livestock predation that causes conflict between carnivores and humans.

  Flipping through my notes in Gnoske’s office, I recalled the observation I’d made in Tsavo that seemed to refute one aspect of his and Kerbis Peterhans’s hypothesis: that the big male, Scarface, appeared to be the leader of a large pride no different from the ones on the Serengeti. Was that an anomaly, and if so, how did they explain it? The question slipped my mind, because I was absorbed in sorting out the facts, theories, and assumptions I’d been scribbling down so feverishly. Also, I was more concerned about determining what significance all the theorizing would have for people outside professional circles. If the two men were able to prove that the buffalo lion was a distinct subspecies, what would the ramifications be? All right, such a discovery would not draw crowds to Times Square to cheer or hoot, but what about its effect in the scientific community? Once again, what did it all mean?

  As if anticipating the question, Kerbis Peterhans had a ready answer.

  “If this proves to be true, it will revolutionize ideas about the role of females in lion society. Beyond lions, it will revolutionize ideas about subspecies, which are now thought to be distinguished geographically. There has to be a significant geographic distance.”

  By way of example, he cited the African and Asian lion and two extinct subspecies, the Barbary lion, which lived in northwest Africa, and the Cape lion, native to South Africa.

  “What we’re saying is that because buffalo lions and pride lions live in the same general area, but look and behave differently, subspecies can be distinguished by morphology, behavior, and ecology.” He paused and then made reference to the invisible elephant in the room. “People are going to look askance because of Tom’s background,” he said, meaning that other scientists were going to question Gnoske’s lack of academic credentials. “That’s why I’ve been extremely careful about gathering enough data and avoiding drawing the wrong assumptions from it.” Another pause. “Two of the Field Museum’s staff who have published in the most scientific journals don’t have any formal training. Neither does [Richard] Leakey himself, yet he’s called ‘Dr. Leakey.’ Tom has made so many remarkable observations that if only a few of them hold up, it will be an achievement.”

  One pat on the back deserved another in return, and Gnoske interrupted to say that his colleague, in addition to acting as a mentor, also helps him navigate in academic and social circles where he feels uncomfortable.

  “I remember when we were in Kenya and we met the ambassador from South Africa. Julian got along with him very well, you know; with his social graces, he mingles very well in high society. We got an invitation from the ambassador to study lions in Kruger National Park.”

  That said, Gnoske added, with utmost serenity, that he felt confident enough in his ideas to publish right now and that the only thing restraining him was Kerbis Peterhans’s insistence on further observations, more data, more measurements.

  Which brought us, finally, to their future plans. Those would be divided into two phases.

  First, they were going to complete their examinations of lion skulls and skeletons, concentrating on those in the American Museum of Natural History in New York and the British Museum, which also housed the skulls of 70 lions shot in Sudan and Ethiopia by Wilfred Thesiger. Now in his 90s, Thesiger, one of the few living figures from the heroic age of exploration, had written that several of the lions had no manes or restricted manes. In taking additional measurements, the two researchers hoped to prove that there are two body types of extant lions.

  “There can be no overlap,” Kerbis Peterhans stressed. “The differences have to be completely discrete.”

  If further study turned up significant overlap, then the hypothesis that buffalo lions are physically different and closer to extinct lions would be disproved. That would not, however, disprove that there are wide variations in behavior and social structure among African lions.

  And so to the second phase: the combined expeditions to the Tana River in eastern Kenya, Uganda’s Queen Elizabeth National Park, and the Luangwa Valley in Zambia. In all three places, Gnoske and Kerbis Peterhans intended to make additional observations of lion behavior, focusing on hunting practices, and to compile data on mane lengths. Their trips to Tsavo and studies they’d made of lions killed by hunters or game rangers had persuaded them that dense vegetation and the prevalence of thorn bushes did not explain how maneless lions get to be that way—plenty of thickly maned lions had been killed in forested country. They believed that mane length in lions with variable manes is controlled by climate and elevation. The Tana River, 600 miles long, would be ideal for testing the theory. With its sources on the slopes of 17,058-foot Mount Kenya, in the Aberdare Mountains, the Tana tumbles down through wooded foothills to stark, scrub-covered plains only a few hundred feet above sea level, then into equatorial rain forests before emptying into the Indian Ocean. If the assumption about elevation and climate was right, then lions found at the high, cold elevations should have thick manes, whereas those at lower, hotter elevations should have sparse manes. For at least half its length, the Tana, a verdant gallery in an arid landscape, also prov
ides the type of riverine environment the hypothesis says is typical buffalo lion habitat. By observing if lions used their forelegs to bring down buffalo or other large game, Gnoske and Kerbis Peterhans could confirm if those carnivores had indeed developed massive bodies to tackle king-size prey. Conversely, the two men could study the carcass of a recent kill, examining it like forensic pathologists to determine how it had met its death. (I recalled Iain Allan’s description of the two males he’d watched dispatching a buffalo on the Galana River. They’d used their brains as much as their brawn.)

  The undertaking would be expensive as well as dangerous, the major danger being posed by our fellow Homo sapiens, not by lions. The danger would in fact contribute to the expense: Gangs of Somali shifta were active in the middle reaches of the Tana, and an expedition there would require adequate security in the form of armed KWS rangers, as many as seven or eight men, all of whom would have to be paid a per diem for up to six weeks. Gnoske and Kerbis-Peterhans were now scratching and scrambling for funding; they and their former boss, Dr. Bruce Patterson, had fallen into a serious disagreement regarding their research and they were now on their own. They promised to keep me abreast of their progress, and if the expedition looked like it was a go, I would of course be welcome to join it. I very much wanted to. While I wasn’t ready to judge if their ideas were valid, I was persuaded that they were doing serious work that could lead to something interesting. Maybe these two Chicago boys were qualified to challenge the prevailing wisdom.

  Well, for an armada of reasons, most having to do with money, the Tana River expedition never came off. The next time I returned to Tsavo it wasn’t with Gnoske and Kerbis Peterhans, but with two scientists who disagreed with them on almost every point and thought the men from the Field Museum were chasing a chimera.