Cinematography by Nathan Williamson

C-Boy (foreground) and Hildur are the resident males for the Vumbi and Simba East prides. These lions need each other as protection from their own species. “The number one cause of death for lions, in an undisturbed environment, is other lions,” says ecologist Craig Packer.

Photograph by Michael Nichols

The lions lie side by side during an afternoon rain shower. C-Boy and Hildur are unrelated but have been a duo for years.

Photograph by Michael Nichols

Hildur shakes the rain from his mane. He and C-Boy work together to retain control over two prides totaling ten adult females.

Photograph by Michael Nichols

Hildur frequently makes a long run from the Vumbi pride to visit the Simba East pride. A coalition that controls two prides must maintain vigilance over both.

Photograph by Michael Nichols

Cinematography by Nathan Williamson

Lions kill lions. The black-maned alpha called C-Boy confronts that peril on a daily (and nightly) basis as he defends his interests with various prides.

Photograph by Michael Nichols

“C-Boy was always grumpy when approached and snarled at both females and cubs,” observed photographer Michael Nichols.

Photograph by Michael Nichols

Asserting his alpha status, C-Boy drags off a freshly killed warthog.

Photograph by Michael Nichols

C-Boy guards a zebra carcass that he took from the females of the Vumbi pride.

Photograph by Michael Nichols

Dry season is hard on everyone. Vumbi females, stressed and fiercely protective of their young, get cross with C-Boy after he snarled at one of the cubs.

Photograph by Michael Nichols

Cinematography by Nathan Williamson

Cubs of the Simba East pride: Too young to kill but old enough to crave meat.

Photograph by Michael Nichols

A female from the Barafu pride wrangles her infant cubs. During the first few weeks, when the infants are too young for the competitive tumble among older cubs in the pride and vulnerable to predators, she keeps them hidden away.

Photograph by Michael Nichols

Young cubs practice their pounce on their mother’s twitching tail.

Photograph by Michael Nichols

Although females show a slight preference for nursing their own, cubs can also suckle from other mothers in the pride.

Photograph by Michael Nichols

These two cubs from the Barafu pride are being raised in the same crèche, even though they are of different ages and mothers. Young cubs can lose out to older ones in the competition for milk and meat.

Photograph by Michael Nichols

Females hide their cubs when they leave to hunt. When they return, the mothers reassure the young lions with licks.

Photograph by Michael Nichols

Despite occasional snarls, such as this warning from C-Boy, males are typically caring and protective fathers.

Photograph by Michael Nichols

Cinematography by Nathan Williamson

After spending the day resting on a kopje, or rocky outcrop, Vumbi pride lions head out for the hunt as night falls.

Photograph by Michael Nichols

Large cubs of the Vumbi pride and a grown female (fifth from left) feast on a wildebeest.

Photograph by Michael Nichols

C-Boy claimed this male eland shortly after the Vumbi pride females made the kill.

Photograph by Michael Nichols

Momentarily distracted from the kill, C-Boy roars in response to jackals calling in the distance.

Photograph by Michael Nichols

After gorging for an hour, C-Boy let the pride eat. Within 15 minutes the pride had consumed the eland.

Photograph by Michael Nichols

Young Maasai warriors wear lion mane headdresses from a lion that was illegally speared three years earlier.

Photograph by Brent Stirton

Maasai warriors participate in a coming-of-age ceremony in a remote village in northern Tanzania.

Photograph by Brent Stirton

An innovative program in Kenya recruits Lion Guardians among the Maasai, some former lion killers, to monitor lion movements and prevent conflicts with herders and cattle.

Photograph by Brent Stirton

Lion Guardians use radio telemetry to locate the big cats outside of Amboseli National Park in Kenya.

Photograph by Brent Stirton

Picture cards help Lion Guardians identify lions. According to photographer Brent Stirton, many of these men recognized the individual lions pictured.

Photograph by Brent Stirton

Although the Maasai have a history of killing lions to protect their livestock, Lion Guardians are the vanguard in helping to reduce human-lion conflict. They work with herders to track down lost livestock and discourage other Maasai from hunting lions.

Photograph by Brent Stirton

Cinematography by Nathan Williamson

C-Boy and a Vumbi female relax between matings. During estrus a single male consort may monopolize a female for days.

Photograph by Michael Nichols

Infrared light illuminates Hildur and a lioness from the Vumbi pride as they rest after mating.

Photograph by Michael Nichols

The females in a pride sometimes reproduce in the same cycle. The practice, known as synchronized estrus, allows the pride to raise their young together and means small cubs don’t have to compete with bigger and hungrier ones.

Photograph by Michael Nichols

C-Boy mates with a Kibumbu pride female. C-Boy and Hildur sired ten cubs with the pride. After they were displaced by a rival coalition dubbed the Killers, all the cubs died.

Photograph by Michael Nichols

Cinematography by Nathan Williamson

Vumbi cubs play at Zebra Kopjes.

Photograph by Michael Nichols

Cubs from the Vumbi pride roughhouse with a lioness.

Photograph by Michael Nichols

Littermates play and spar, often mimicking adult behavior.

Photograph by Michael Nichols

The Vumbi cubs are always up for a game, as photographer Michael Nichols discovered when they chased each other early one morning.

Photograph by Michael Nichols

Hildur reacts with surprise when a young Vumbi female jumps on his back. It was a rare moment of aggression from the golden-maned lothario.

Photograph by Michael Nichols

Cinematography by Nathan Williamson

Lionesses from the Vumbi pride take an afternoon nap. Lions sleep up to 20 hours a day, typically resting during daytime to beat the heat.

Photograph by Michael Nichols

Female lions raise their cubs, like these Vumbi youngsters, together as a crèche, or nursery group.

Photograph by Michael Nichols

The Vumbi pride searches for water at Zebra Kopjes. The Vumbi females have successfully raised 8 of the 14 cubs born in April 2011.

Photograph by Michael Nichols

Photographer Michael Nichols first met the Vumbi pride at the height of the dry season, when food was scarce. By the time of their second encounter, the rains had come. Here, a lioness sniffs the air for signs of prey.

Photograph by Michael Nichols

Hildur, a resident male with the Vumbi pride, claims his share of a buffalo carcass that the females in the pride brought down. Males often assert their dominance at kill sites.

Photograph by Michael Nichols

Eight Vumbi cubs, all about a year old, rest in tall grass after a successful hunt the night before. Photographer Michael Nichols made this image as he perched on the roof of his Land Rover.

Photograph by Michael Nichols

Cinematography by Nathan Williamson

Photographer Michael Nichols used a small remote-controlled helicopter to get a bird’s-eye view of the Vumbi pride resting on Barafu Kopjes.

Photograph by Michael Nichols

“We know that lions prefer to hang out around river confluences, where there’s cover, where there’s water, where the prey have to make a crossing,” says Craig Packer. “The lions can sit and wait for their next meal.” Here, wildebeest cross the Mara River as part of their annual migration.

Photograph by Michael Nichols

Despite having observed lions for decades, Craig Packer has never seen them kill a giraffe. “I would love to know how they do it,” says Packer. “I’ve seen footage of females actually run all the way up the back of the giraffe, hold on and try to pull it down. They’re not big enough.”

Photograph by Michael Nichols

Savanna elephants move across the plains. Lions are the only predators strong enough to take down an elephant. According to Karen McComb of the University of Sussex, older elephant matriarchs can distinguish between male and female lion roars. If they hear a male, they gather the herd together for protection.

Photograph by Michael Nichols

The short rainy season draws in the large herds that provide sustenance for lions. Here, zebras graze after a late afternoon storm.

Photograph by Michael Nichols

Nowhere else in Africa supports such a concentrated abundance of hoofed meat on such open landscape. “The Serengeti is a glorious place for lions and an ideal site for lion researchers,” says David Quammen, author of the August National Geographic features “The Short Happy Life of a Serengeti Lion” and “Living With Lions.”

Photograph by Michael Nichols

Cinematography by Nathan Williamson

Of encountering the Killers for the first time after hearing about them for so long, photographer Michael Nichols says, “I was petrified. They had just returned from marauding and were in a pack looking like a gang. We were very close, it was getting dark, and we didn’t trust them. It was a tense situation.”

Photograph by Michael Nichols

Females of the Kibumbu pride lead the cubs to a waterhole, while looking out for the Killers. In an undisturbed ecosystem, a quarter of cubs die from infanticide, according to ecologist Craig Packer.

Photograph by Michael Nichols

Cinematography by Nathan Williamson

A curious Vumbi female takes a gentle swipe at the remote-controlled “tank,” which provided a lion’s-eye view of pride behavior.

Photograph by Michael Nichols

The Vumbi pride quickly got used to the robot. Nichols and Williamson operated the tank together, with Nichols working the still camera and Williamson steering and shooting video.

Photograph by Michael Nichols

Cinematography by Nathan Williamson

Daniel Rosengren, a member of the Serengeti Lion Project, finds the Barafu pride far outside their territory. Sammy, the pride’s resident male (in the foreground), was no match for the invading Killers. He has since disappeared.

Photograph by Michael Nichols

“You would be amazed how many people have asked me about The Lion King as if it’s a biology lesson,” says Craig Packer. “I mean, come on! Do we really understand rabbit behavior from Bugs Bunny and duck behavior from Daffy and rodent behavior from Mickey?” Packer and his team at the Serengeti Lion Project spend endless hours tracking lions to gain insights into their behavior and their role in the ecosystem. Team members are (from left) Daniel Rosengren, Ali Swanson, Craig Packer, Ingela Jansson, and Stan Mwampeta.

Photograph by Michael Nichols

A captive-bred lioness at a farm in South Africa will be raised to maturity, bred, and then released to be hunted within a confined area. Many people, including hunters, question whether the ranches satisfy the ethic of fair chase.

Photograph by Brent Stirton

Doornkop Farm is one of the largest lion-breeding facilities in South Africa. There are 500 to 600 lions at the farm at any given time; the majority will eventually be sold for hunting.

Photograph by Brent Stirton

These cubs are among the thousands of lions raised in captivity to sustain the game-hunting industry in South Africa.

Photograph by Brent Stirton

Steve Sibrel, an American bow hunter, hunts lions with professional guides at a game farm in South Africa.

Photograph by Brent Stirton

Sibrel (at left) killed this lioness on a South African ranch.

Photograph by Brent Stirton

Legally hunted lions in South Africa yield skeletons that are exported for traditional medicines, mostly to Asia. With tigers reduced to a few thousand in the wild, lion bones are gaining popularity.

Photograph by Brent Stirton

Cinematography by Nathan Williamson

As the light goes down, the lions perk up. “They reaffirm bonds,” says Nichols. “They’ll do a lot of licking, and everyone says hello.”

Photograph by Michael Nichols

When the migration moved through their territory, the Vumbi pride settled near a waterhole to take advantage of easy access to prey and water.

Photograph by Michael Nichols

When the sun sets, it’s time for the Vumbi pride to get to work. A still camera mounted on a remote-controlled robot allowed photographer Michael Nichols to take this close shot of the Vumbi pride as its members began to rouse themselves for a hunt.

Photograph by Michael Nichols

Dusk is a busy time for the Vumbi pride. As the moon rises, the lionesses awake from their afternoon naps and set out on the evening hunt.

Photograph by Michael Nichols

Cinematography by Nathan Williamson

The Vumbi females—their pride name is Swahili for “dust”—kill a warthog they’ve dragged from its burrow. Such small kills help bridge the lean, hungry dry season, when cubs may otherwise starve.

Photograph by Michael Nichols

The Vumbi females—their pride name is Swahili for “dust”—kill a warthog they’ve dragged from its burrow. Such small kills help bridge the lean, hungry dry season, when cubs may otherwise starve.

Photograph by Michael Nichols

The Vumbi females—their pride name is Swahili for “dust”—kill a warthog they’ve dragged from its burrow. Such small kills help bridge the lean, hungry dry season, when cubs may otherwise starve.

Photograph by Michael Nichols

Yusufu Shabani Difika lost his arms in a lion attack in Tanzania’s Selous Game Reserve. Here his uncle bathes Difika, a father of two.

Photograph by Brent Stirton