This story appears in the August 2013 issue of National Geographic magazine.

They say that cats have nine lives, but they don’t say that about the Serengeti lion. Life is hard and precarious on this unforgiving landscape, and dead is dead. For the greatest of African predators as well as for their prey, life spans tend to be short, more often terminating abruptly than in graceful decline. An adult male lion, if he’s lucky and durable, might attain the advanced age of 12 in the wild. Adult females can live longer, even to 19. Life expectancy at birth is much lower, for any lion, if you consider the high mortality among cubs, half of which die before age two. But surviving to adulthood is no guarantee of a peaceful demise. For a certain young male, black-maned and robust, known to researchers as C-Boy, the end seemed to have arrived on the morning of August 17, 2009.

A Swedish woman named Ingela Jansson, working as a field assistant on a long-term lion study, was there to see it. She knew C-Boy from previous encounters; in fact, she had named him. (By her recollection, she had “boringly” labeled a trio of new lions alphabetically as A-Boy, B-Boy, and C-Boy.) Now he was four or five years old, just entering his prime. She sat in a Land Rover, 30 feet away, while three other males ganged up on C-Boy and tried to kill him. His struggle to survive against those daunting odds, dramatic in itself, reflected a larger truth about the Serengeti lion: Continual risk of death, even more than the ability to cause it, is what shapes the social behavior of this ferocious but ever jeopardized animal.

On the day in question, near the dry bed of the Seronera River, Jansson came to check on a pride known as Jua Kali. She was also alert for adult males, including those “resident” with the pride. (Male lions, not strictly belonging to any pride, instead form coalitions with other males and exert controlling interest over one or more prides, fathering the cubs and becoming resident, loosely associated with the pride. They also play an important role in helping kill prey—especially with larger and more dangerous animals, such as cape buffalo or hippos—thereby contributing something besides sperm and protection to the life of the pride.) The resident males of Jua Kali, Jansson knew, were C-Boy and his sole coalition partner, a golden-maned lothario named Hildur. Approaching the river, she saw in the distance one male being chased by another. The fleeing lion was Hildur. Fleeing from what, and why, she didn’t at first understand.

Then she found a group of four males in the grass. They had settled themselves in a squarish pattern, each about five strides away from the others. She recognized them—some of them, anyway—as members of another coalition, a group of four ambitious young adult males, notorious in her record cards as the Killers.

One lion had a bloody tooth, the lower right canine, suggesting a very recent fight. Another was hunkered flat, as though wishing he could disappear into the ground. From the flattened male came a steady, nervous growl. Driving closer, Jansson saw the dark tinge of his mane and realized this was C-Boy, wounded, isolated, and surrounded by three of the Killers.

She had also noticed a lactating female, the radio-collared lioness of the Jua Kali pride. Lactation meant young cubs, hidden somewhere in a den, the presumptive father of which was C-Boy or Hildur. So this standoff between C-Boy and the Killers was more than a pointless rumble. It was a challenge for controlling rights to a pride. If the new males took over, they would kill the young of their rivals to bring the females quickly back into heat.

Seconds later, the fight erupted again. The three Killers circled C-Boy and took turns lunging at him from behind, lashing into his haunches, biting at his spine, as he spun and snarled and rolled desperately to escape. Close enough almost to feel the spray of spit, to smell the malice, Jansson gaped from her car window, taking photos. Dust flew, C-Boy whirled and roared, and the Killers played their advantage, avoiding his jaws, backing off, coming at him again from the rear, sinking their teeth, scoring hurts, until the hide of his hindquarters looked like a perforated old pelt. Jansson thought she was witnessing the terminal event of a lion’s life. If the immediate injuries didn’t kill him, she reckoned, the later bacterial infections would.

Then it was over, as abruptly as it had begun. Maybe a minute of fighting. They separated. The Killers strolled off and positioned themselves atop a termite mound, with a commanding view of the river, while C-Boy slunk away. He was alive, for the moment, but defeated.

Jansson didn’t see him for two months. He might have been dead, she guessed, or at least debilitated. In the meantime the Killers began having their way with the Jua Kali females. The small cubs of C-Boy’s or Hildur’s paternity disappeared—killed by the conquering males, or maybe abandoned to starvation, or neglected just enough to get eaten by hyenas. The females would go back into estrus now, and the Killers would father new litters. C-Boy was yesterday’s favorite, yesterday’s stud. The Jua Kalis would forget him. This is the cold arithmetic of lion society.

View Images Cubs of the Simba East pride: too young to kill but old enough to crave meat. Adult females, and sometimes males, do the hunting. Zebras and wildebeests rank high as chosen prey in the rainy season.

Tigers are solitary. Cougars are solitary. No leopard wants to associate with a bunch of other leopards. The lion is the only feline that’s truly social, living in prides and coalitions, the size and dynamics of which are determined by an intricate balance of evolutionary costs and benefits.

Why has social behavior, lacking in other cats, become so important in this one? Is it a necessary adaptation for hunting large prey such as wildebeest? Does it facilitate the defense of young cubs? Has it arisen from the imperatives of competing for territory? As details of leonine sociality have emerged, mostly over the past 40 years, many of the key revelations have come from a continuous study of lions within a single ecosystem: the Serengeti.

Serengeti National Park encompasses 5,700 square miles of grassy plains and woodlands near the northern border of Tanzania. The park had its origin as a smaller game reserve under the British colonial government in the 1920s and was established formally in 1951. The greater ecosystem, within which vast herds of wildebeest, zebra, and gazelle migrate seasonally, following the rains to fresh grass, includes several game reserves (designated for hunting) along the park’s western edge, other lands under mixed management regimes (including the Ngorongoro Conservation Area) along the east, and a transboundary extension (the Masai Mara National Reserve) in Kenya. In addition to the migratory herds, there are populations of hartebeests, topi, reedbuck, waterbuck, eland, impalas, buffalo, warthogs, and other herbivores living less peripatetic lives. Nowhere else in Africa supports quite such a concentrated abundance of hoofed meat, amid such open landscape, and therefore the Serengeti is a glorious place for lions and an ideal site for lion researchers.

George Schaller arrived in 1966, by invitation of the director of Tanzania National Parks, to study the effects of lion predation on prey populations—and to learn as much as he could, in the process, about the dynamics of the entire ecosystem. Schaller, a legendarily tough and astute field biologist, had earlier done pioneering research on mountain gorillas. If you’re making the first detailed study of any species, he told me recently, “you grab what you can.” He grabbed a cornucopia of data during three and a quarter years of intensive fieldwork, and his subsequent book, The Serengeti Lion, became the foundational text.

Other researchers followed. A young Englishman named Brian Bertram succeeded Schaller and stayed four years, long enough to begin teasing out the social factors that affect reproductive success and to explain an important phenomenon: male infanticide. Bertram documented four cases (with many others suspected) in which a new coalition of males killed cubs of a pride it had just taken over. Jeannette Hanby and David Bygott came next and assembled evidence that forming coalitions—especially coalitions of three or more—helps male lions gain and hold control of prides and thereby produce more surviving offspring. Hanby and Bygott studied some of the same prides in the same areas as Bertram and Schaller had.

Then, in 1978, Craig Packer and Anne Pusey took over the study, after having done fieldwork at the Gombe Stream Research Center (also in Tanzania) with Jane Goodall. Pusey stayed with the lion project a dozen years, co-authoring some important papers, and Packer is still on the case, leading the Serengeti Lion Project, of which Ingela Jansson’s work is part. He is arguably now the world’s leading authority on the behavior and ecology of the African lion. With Packer’s 35 years of work added to what Schaller and the others did, the Serengeti Lion Project represents one of the longest continuous field studies of a species. Such continuity is especially valuable, allowing scientists to set events in broad context and distinguish the transitory from the essential. “If you have a long-term data set,” Schaller told me, “you find out what actually happens.”

One thing that happens is death. Although it’s ineluctable for every creature, the particulars of timing and cause add up to patterns that matter.

View Images In 2009 a gang of lions called the Killers attacked C-Boy. Ingela Jansson, then a research assistant with the Serengeti Lion Project, photographed the fight. C-Boy survived, but the Killers drove him away from the Jua Kali pride—where he and Hildur had been the resident males.

After his harrowing experience with the Killers, C-Boy surrendered his claim on the Jua Kali pride and shifted his attentions east. Hildur, his coalition partner, who’d been so little help in the pinch, went with him. By the time I got a glimpse of C-Boy three years later, he and Hildur had established control over two other prides, Simba East and Vumbi, whose territories lay amid the open plains and kopjes (rocky outcrops) south of the Ngare Nanyuki River. This is not the most hospitable part of the Serengeti for lions and their prey—during the dry season it can be lean and difficult—but it offered C-Boy and Hildur an opportunity to start fresh.

I was traveling through that area with Daniel Rosengren, another adventuresome Swede, who had taken over the lion-monitoring role from Jansson. Way out here, east of the main tourism area and south of the river, the great vistas of grassland rise and fall smoothly, like oceanic swells, punctuated every few miles by a cluster of kopjes. The kopjes, granitic lumps festooned with trees and shrubs, standing above the plains like garnished gumdrops, offer shade and security and lookout points for resting lions. You can drive for days in this corner of the park and not see a tourist vehicle. Along with Michael (Nick) Nichols and his photo team, who were spending months at a field camp up by the riverbed, we had the area to ourselves.

That afternoon the radio signal in Rosengren’s headphones led us to Zebra Kopjes, where, amid the cover, we found the collared female of the Vumbis. Beside her was a magnificent male with a thick mane that cascaded off his neck and shoulders like a velvet cape, shading from umber to black. It was C-Boy.

View Images Infrared light illuminates Hildur and a lioness from the Vumbi pride as they rest after mating. The females in a pride sometimes reproduce on the same cycle. This allows the pride to protect and feed their young together.

From just 40 feet away, even through binoculars, I could detect no sign of injuries to his flanks or his rear. The punctures had healed. “On lions,” Rosengren told me, “most scars disappear after a while, unless they’re around the nose or mouth.” C-Boy had made a new life for himself in a new place, with new lionesses, and seemed to be thriving. He and Hildur had fathered several more litters of cubs. And just the night before—so we heard from Nichols, who had seen it—the Vumbi females brought down an eland, a very large hunk of prey, after which C-Boy had laid his imperious male forepaw on the carcass, claiming first bites. C-Boy had fed on the eland alone, taking choice morsels but not too much, before allowing the lionesses and their cubs to get at it. Hildur had been elsewhere, presumably consorting with another estrous female. So they were living the good life, those two, with all the prerogatives of resident male lions. This was just 12 hours before we saw evidence suggesting that trouble had followed them east.

The trouble was male competition. Early next morning Rosengren drove us north from Nichols’s camp to the river, seeking a pride known as Kibumbu, whose small cubs had been fathered by still another coalition. Those males had gone absent in recent months—departed to places unknown, for reasons unknown—and Rosengren wondered who might have supplanted them. That was his assignment, within the broader context of Packer’s lion studies: to chronicle the comings and goings, the births and the deaths, the affiliations and retreats that affect pride size and territorial tenure. If the Kibumbus had new daddies, who might they be? Rosengren had a suspicion—and it was confirmed when, amid the high grass of the riverbank, we came upon the Killers.

They were handsome devils, a quartet of eight-year-old males, resting in a companionable cluster. They looked forbidding and smug. They’re probably two sets of brothers, Rosengren told me, born within months of each other in 2004. They had been dubbed “the Killers” back in 2008 by another field assistant, based on his inference that they’d killed three collared females, one by one, rather systematically, in a drainage just west of the Seronera River. Such male-on-female violence wasn’t utterly aberrant—it might even be adaptive for males in some cases, opening space for prides that they control by removing competition in the form of neighboring females—but in this case it won the males a malign reputation.

Understanding the Lives of Lions What makes lions social? Are they really lazy—or just very patient? Craig Packer, director of the Serengeti Lions Project, has spent decades deciphering the riddles of one of nature's most familiar creatures.

Although Rosengren told me their individual names as recorded on the cards (Malin, Viking, et cetera), his preference was to call them by their numbers: 99, 98, 94, 93. Those numerals did seem somehow more concordant with their air of opaque, stolid menace. Male 99, seen in profile, had the convex nose line of a Roman senator, as well as a darkish mane, though not so dark as C-Boy’s. Inspecting him through binoculars, I noticed a couple of small wounds on the left side of 99’s face.

Rosengren eased the Land Rover closer, and two of the others, 93 and 94, stirred, turning toward us. In the golden light of sunrise we saw facial injuries on them too: a slice to the nose, a bit of swelling, a gash below the right ear still glistening with pus. Those are fresh, Rosengren said. Something happened last night. And not just a spat over shared food; coalition partners don’t do such damage to one another. It must have been a brawl with other lions. That raised two questions. Whom had the Killers fought? And what did the other guy look like this morning?

Then, as the day progressed and we made other rounds, it seemed that C-Boy was missing.

“Mostly lions die because they kill each other,” Craig Packer told me, in response to a question about fatalities. “The number one cause of death for lions, in an undisturbed environment, is other lions.”

He broke that into categories. At least 25 percent of cub loss is owed to infanticide by incoming males. Females too, given the chance, will sometimes kill cubs from neighboring prides. They will even kill another adult female, he said, if she unwisely wanders into their ambit. Resources are limited, prides are territorial, and “it’s a tough ’hood out there.”

Males operate just as jealously. “Male coalitions are gangs, and if they find a strange male that’s hitting on their ladies, they’ll kill him.” And males will kill adult females if it suits their purposes, as the Killers had shown. You see a lot of bite wounds on lions, reflecting the competitive struggle for food, territory, reproductive success, sheer survival. With luck, the wounds heal. Less luck, and the loser is killed in a fierce leonine battle, or he limps away, losing blood, maybe crippled, maybe destined to die slowly of infection or starvation. “So the lion is the number one enemy of lions,” Packer said. “It’s why, ultimately, lions live in groups.” Holding territory is crucial, and the best territorial locations—places he calls hot spots, such as stream confluences, where prey tend to become concentrated—serve as incentive for social cooperation. “The only way you can monopolize one of those very valuable and very scarce hot spots,” he says, thinking like a lion, is as “a gang of like-sexed companions who work as a unit.”

View Images A female wrangles her infant cubs. During the first few weeks, when they’re too young for the competitive jumble among older cubs in the pride and so vulnerable to predators, she keeps them hidden away in a den. But these will soon join the group.

That theme has emerged strongly from Packer’s research, done with various collaborators and students over the decades. It’s not just the need for joint effort in making and defending kills, he has found, that drives lionesses to live in prides. It’s also the need to protect offspring and retain those premium territories. His data show that, although pride size varies widely, from just one adult female to as many as 18, prides in the middle range succeed best at protecting their cubs and maintaining their territorial tenure. Prides that are too small tend to lose cubs. Periods of estrus for the adult females often are synchronized—especially if an episode of male infanticide has killed off all their young and reset their clocks—so that cubs of different mothers are born at about the same time. This allows the formation of crèches, lion nursing groups in which females suckle and protect not just their own cubs but others too. Such cooperative mothering, efficient in itself, is further encouraged by the fact that the females of a pride are related—as mothers and daughters and sisters and aunts, sharing a genetic interest in one another’s reproductive success. But prides that are too large do poorly also, because of excessive within-pride competition. A pride of two to six adult females seems to be optimal on the plains.

Male coalition size is governed by similar logic. Coalitions are formed, typically, among young males who have outgrown the natal pride and gone off together to cope with adulthood. One pair of brothers may team with another pair, their half-siblings or cousins, or even with unrelated individuals that turn up, solitary, nomadic, and needing partnership. Put too many such males together as a roving posse, each hungry for food and for chances to mate, and you have craziness. But a lone male, or a coalition that’s too small—just a pair, say—will suffer disadvantages also.

That was C-Boy’s dilemma. With no partner other than Hildur, a handsome enough male who showed great eagerness to mate but little to fight, C-Boy confronted the Killers, in their aggressive ascendancy, virtually alone. Not even his resplendent black mane could neutralize three-against-one odds. Maybe by now he was already dead. If so, Rosengren and I realized, those minor battle injuries on the faces of the Killers might be the last evidence of C-Boy that anyone would ever see.

View Images The Killers, a male coalition of four, earned their name with lethal attacks on females. They almost killed their rival C-Boy too. Because good territory is a precious resource, fighting and displacing competitors are part of the natural struggle.

That night the Killers made another move into new territory. They had rested all day by the riverbank, letting the sun cook their faces and dry their sores. About two hours after sunset, they started roaring. Their joined voices broadcast a message of some sort—maybe, Here we come!—into the distance. Then they set out, all four together, on what looked like a purposeful march. Rosengren and I got the word by walkie-talkie from Nichols, who had been keeping vigil. We jumped into Rosengren’s Land Rover and headed out through the blackness, beginning what I recall as the Night of the Long Follow.

Converging with Nichols’s vehicle, we climbed in and stayed with the lions—five of us now, Nichols’s wife, Reba Peck, at the wheel, easing along, headlights dimmed. There was no moon. Nichols had night vision goggles and an infrared camera. His assistant and videographer, Nathan Williamson, sat ready to capture sound or deploy the infrared floods. We were a journalistic gunship, bristling with armaments, rolling slowly along behind the lions. They showed no concern whatsoever about our presence. They had other things in mind.

We followed them up an old buffalo track, then through a tight grove of fever trees, Peck coaxing the car patiently around aardvark holes, over crunching thorn branches, across a sumpy stream bottom. Please don’t get stuck, we all thought. With four Killers nearby, nobody wanted to climb out and push. We didn’t get stuck. The lions walked in single file, steady, unhurried, neither waiting for us nor trying to lose us. We kept them in view with the low headlights and, where those didn’t reach, a monocular thermal scope. Through the scope, as I sat atop the Rover’s jouncing roof, I saw four lion bodies glowing like candles in a cave.

Suddenly another large figure swung up alongside us, its eyes shining orange when I swept it with my headlamp. It was a lioness, making herself known to the Killers. Rosengren couldn’t recognize her, in this fleeting glimpse, but presumably she was in heat. So she was taking sex-mad risk, probably larger than she could guess, given the record of these particular males. When they noticed her, and wheeled toward her, she ran off coyly, pursued by all four, and for a moment we thought we had lost them. But only one male stayed on her tail; we wouldn’t see him again all night. The other three reassembled themselves, after this flirty distraction, and continued their march.

View Images Older cubs like these Vumbi youngsters are raised together as a crèche, or nursery group. Pride females, united in the cause of rearing a generation, nurse and groom their own and others’ offspring.

They crossed a dirt two-track (the main east-west “road,” which we used coming and going to camp) and angled south, now brazenly entering the territory of the Vumbi pride and its resident defenders, C-Boy and Hildur. They paused here and there to scent mark, rubbing their foreheads against bushes, scratching and spraying the ground. This wasn’t a sneak attack; they were advertising themselves, making a statement. Too bad, Rosengren noted, that we don’t have some sort of fancy scope to illuminate those smells.

By now they had turned and were headed toward Nichols’s camp, so Williamson radioed ahead and warned the kitchen crew to stay in their tents. But the three lions didn’t care about our little canvas compound, with its odors of popcorn and chicken and coffee, any more than they cared about us; about a quarter mile short, they bedded down to rest. During this hiatus, just before midnight, Nichols and his team went back to camp. Rosengren and I, having retrieved the other vehicle, stayed with the Killers. He took the first sleeping shift, snoring gently in the back of the Land Rover, while I sat up, keeping watch. Half an hour later the lions stood and began moving again; I woke Rosengren, and we followed.

And that’s how it went—a stretch of walking, a stretch of sleeping, Rosengren and I trading duties—for the rest of the night. Occasionally, during a stop, they let their voices rise in another chorus of roars. The roar of three lions heard at close range, let me tell you, is an imposing sound: high in decibels but throaty and rough, as though scraped up from a deep iron bin of primordial power and confidence and threat. No one answered these calls. In the wee hours the trio met a lone Thomson’s gazelle; that poor gazelle must have been terrified, but as the lions made a perfunctory try, it bounded safely away. One tommy, divided three ways, was scarcely worth the trouble. As dawn came, they were back on the road after their big loop through Vumbi territory, strolling casually west toward a familiar kopje where they would find shade or the day. It was Saturday morning. Rosengren and I left them there.

The wounds on their faces, and the absence of C-Boy, were still unexplained. Lion politics along the Ngare Nanyuki River seemed to be in flux.

Late Saturday afternoon, we found the Vumbi pride at Zebra Kopjes, a couple of miles south of where the Killers had made that intrusive circuit. Maybe the pride had been driven down there by the minatory roaring, or maybe they had just wandered. We counted three females, resting contentedly amid the shaded lobes of granite, and all eight cubs. Another female, we knew, was off on a mating foray with lover boy Hildur. No sign of C-Boy. His absence seemed slightly ominous.

Sunday afternoon, back to Zebra Kopjes. Hildur and his female had rejoined the group, but not C-Boy. Let’s try Gol Kopjes, Rosengren suggested. With luck we’ll see the Simba East pride, and he might be with them. Yes, I said; that’s my priority, I want to find him, dead or alive. So we drove southwest, rising and descending gently across the swales of grassland, while Rosengren listened in his headphones for the bleeps of Simba East. At a small kopje near the main Gols we located them: three females and three large cubs, lounging amid the radiant rocks. But again, no sign of C-Boy.

Rosengren, at this point, admitted to some worry. His job was not to root for favorites, of course, but to monitor events, including the natural phenomena of lion-on-lion violence and pride takeover; but he had his sympathies. It’s beginning to seem, he said sadly, that C-Boy must have fallen victim to the Killers.

With a lavender Serengeti sunset painting the horizon behind us, we drove back to Zebra Kopjes. Nichols and Peck were still there, with the Vumbis, who had hunkered together in the grass and begun roaring—one voice, then another, then three together, rumbling out across the plains beneath a now darkening sky and a small waxing crescent of moon. Lion roars can carry a range of meanings, and this chorus bore a mysterious, lonely tone. When they fell silent, we listened with them. No response.

View Images A male often asserts his prerogatives. C-Boy feasts on a zebra while the Vumbi females and cubs wait nearby, warned off by his low growls. Their turn will come.

Nichols and Peck departed for camp. Rosengren circled our vehicle into a spot just beside the reclining Vumbis. He wanted me to experience the fearsome thrill of taking lion roars point-blank in the face. This time Hildur joined in, his deep male basso rasping and thundering, almost shaking the car. Once they finished, we again listened intently. And again nothing. Now I was ready to leave. For journalistic purposes, I was prepared to list C-Boy as “missing, suspected dead.”

Wait, Rosengren said. There was a scuffle in the darkness around us. Give me your headlamp, he said. Swinging the beam from left to right, across Hildur and the others, Rosengren brought it to rest on a new figure, a large one, with a very dark mane: C-Boy. He was back. He had come running to the sound of their roars.

His face was smooth. His flanks and buttocks were intact. Whomever the Killers had mugged two nights ago, it wasn’t him. He settled comfortably beside the collared female. Soon he’d be mating again. He was an eight-year-old lion, healthy and formidable, commanding respect within a pride.

It was all very temporary. C-Boy’s life might stretch forward a few years, beyond this moment, into infirmity, injury, mayhem, displacement, starvation, and death. The Serengeti offers no mercy to the elderly, the unlucky, or the impaired. He wouldn’t always be happy. But he looked happy now.