True, her first adoptee was devoured in January by another lion that had a clearer sense of the proper predator-prey relationship. Since then, government rangers intervened to rescue each baby oryx as it weakened from lack of food. Their birth mothers, needless to say, were too afraid of the lingering lion to drop by and nurse their young.

The latest adoption came this week, when the driver of a safari van spotted the lioness early Monday morning with a wobbly little oryx, its umbilical cord still attached. The driver notified others, and soon Kamuniak and her new baby oryx were under full-time observation. But this time, Samburu's rangers decided not to intervene but to let nature take its course.

On Wednesday afternoon the two were spotted sleeping not far from each other, under separate acacia trees. Eventually the oryx awoke with a bleating sound not unlike that of a goat. The lioness heard the cry and, ever so slowly, ambled over toward the newborn, who walked away through the bush.

As the promenade began, vans hurriedly repositioned themselves for a better view.

At one point the mother oryx appeared on the scene and rangers tried to use their vehicle to block the lioness and permit a mother-calf reunion. But the lioness would have none of that. She trotted around the rangers and took control of the oryx again.

The lioness typically forgoes hunting while raising an antelope, apparently too concerned about the safety of the oryx to venture too far afield. Some months back she did catch a gerenuk, another kind of antelope, that happened to amble by while she was tending to her third adopted oryx. This week the lioness eyed a small group of wildebeest and even got into her hunter's crouch, but the oryx strayed away and the lioness soon pranced off after it.

All the tenderness that the lioness displayed temporarily changed the dynamics of game viewing in the reserve.

''Everyone always seems to enjoy a kill,'' said Julius Kimani, a senior warden with the Kenya Wildlife Service. ''It's a rare thing to see a predator running after a prey. But this is even more rare. You have a predator who is caring for its prey.''