Killer Pride A dance of death links lions and buffalo in Botswana's Okavango Delta.

1. Killer Pride A dance of death links lions and buffalo in Botswana's Okavango Delta. • By Dereck Joubert Lions usually hunt at night, or at least in the cool hours of dawn and dusk. But when the midday heat climbs to 120°F, the lions of Duba Plains are just starting to stalk their prey. It's one of many uncommon traits of a pride of lions that lives in an intimate relationship with a herd of Cape buffalo on a marshy island in the Okavango Delta. The nine lionesses of the Tsaro pride (tsaro is the local name of the palms they like to rest under) rarely let the herd out of their sight, and attack this ready meat supply with little of the usual lioness stealth. When hunting, they run directly at their prey. Each month the lions kill about 22 members of the resilient herd that numbers more than a thousand. Painted with the blood of a hard-won meal, this lioness pauses to make sure the herd isn't going to rally. Cape buffalo are always formidable prey, but, surprisingly, the Duba herd has learned to fight back as a unit. Buffalo returned the cats' aggression in more than three-quarters of the hunts we observed during two years at Duba, sometimes fatally injuring the lionesses. The buffalo are capable of fleeing the island, especially during the dry season, when the surrounding rivers are fordable. But they stay, the strategy seeming to be: Better the enemy you know.

2. Rarely witnessed behavior marks the predator-prey relationship of a pride of lions and a herd of Cape buffalo on a marshy island in Botswana's Okavango Delta.

3. Lions sharing a marshy island with a herd of Cape buffalo in Botswana's Okavango Plains: Seems like a life of easy hunting for the lions. The nine lionesses of the Tsaro pride on Duba Island attack this ready supply of meat almost daily. But pulling down a meal isn't always a sure thing: The buffalo fight back with swinging horns and slashing hooves. The downed cow in this photo has been wounded. Six times members of her kinship group rushed in to repel the lions and tried to get her back on her feet. The lions persevered, and the cow was ultimately killed and eaten.

4. Charging through the marsh, members of the Tsaro pride display their extraordinary strength. They are the largest lions that Beverly and Dereck Joubert have seen in their decades of documenting African wildlife. Lions don't take naturally to water, but at Duba they've become swamp cats-running, jumping, wading, even swimming to reach their buffalo prey. This rigorous aquatic workout, coupled with a steady buffalo-meat diet, accounts for their grand physiques.

5. Whenever the buffalo herd ventures too close to leaving the Tsaro pride's territory, the lionesses try to turn the herd back. But they have to watch out for straggling bulls. These massive male buffalo are strong and aggressive. Although desperate to join up with the rest of the herd, bulls of this age are also eager to engage and chase lions, lunging at them with sharp horns and trying to run them down. It is a dance where lions chase buffalo and buffalo chase lions.