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.