Samburu is one of the most famed East African wildlife sanctuaries, situated 300 kilometers (under 200 miles) northeast of Nairobi. The lioness, first seen with her young friend at the base of Lolgotoi Hill on Easter weekend, has been attracting thousands of visitors ever since.

The story of this spectacular friendship represents a radical departure from both animals' natural instincts, say wildlife experts. Ordinarily the lioness would have killed the oryx for a meal but instead, the predator escorted it around Samburu, keeping away other predators. A top carnivore making an alliance with an herbivore, its usual prey, defies all logic.

But this isn't the first time the lioness has baffled and delighted onlookers with such unlikely maternal behavior. In the final week of 2001, observers say, she "adopted" her first baby oryx, whom she sheltered from other predators as the two wandered the game reserve together for two weeks, before another lion killed the oryx in early January of this year. It is reported that she roared in grief for hours. The second adoption lasted less long, as park authorities in February took away the small oryx after only a few days in Kamuniak's custody.

Unlike in the last two instances, Samburu game warden Simon Leirana says he hopes this third adoption ends more happily. "To make sure the law of the jungle does not reign supreme again, we have mounted a round the clock watch over the odd couple," he says. "All wardens now have orders to keep away other lionesses in the pride — and particularly the lion that made a meal of the first oryx baby.''

He adds they are going to observe the intimate relationship very closely to ensure the oryx's safety. The lioness, however, has shown extreme maternal concern for all the baby oryxes. In the first case, she starved for 17 days while watching over the oryx, whom she allowed to make regular visits to its lactating mother. At one stage, the lioness chased off a family of cheetahs that tried to kill the calf. But sadly, many said inevitably, the oryx was eventually killed by another passing lion.

When the second calf and its mother were separated on Valentine's Day, the lioness adopted it as well, but game wardens surrounded and tranquilized the frail calf while the lioness hunted. The oryx, weak from hunger, was loaded gently into a vehicle and taken to Lewa Downs, a private game sanctuary some kilometers away.

The strange relationship has the wardens and naturalists at the park puzzled. Wildlife experts have offered a range of scientific explanations, with most attributing the adoption to unfulfilled maternal instincts.

Some suggested the lioness may be unable to conceive her own cub, and has taken to satisfying her natural instincts through another species. But none could say why she is so fond of the oryx, nor why she turned to a prey species instead of adopting, say, a lion cub.

Experts have suggested that wildlife authorities could intervene and help the lioness get over its fixation by conceiving its own cub or adopting one from another pride.

But the villagers, wildlife workers, journalists and tourists who have been flocking to Samburu to witness the pair — a group that includes American country musician Kenny Rogers — are not interested in logic. Their interest is in the odd friendship, which feels to many like a message of decency and love in a world full of sectarian violence.

Tourists have been watching daily in disbelief as the lioness and the frail brown calf walk side by side and lie down to rest together, with all the intimacy of a mother and her cub.

''It's too good to be true. I came to see lion maul the oryx in its true habitat. But this what I see,'' said Aleks Stutton from Geneva, Switzerland.

So far, no one has come up with a scientific explanation. But many questions linger. Has the lioness really adopted the oryx as her own? Or does the animal — the queen of beasts, after all — intend to make a meal of it in the future?

The two animals have sharply contrasting habits. Lions sleep up to 16 hours a day, waking only to hunt and eat browsers like antelopes, waterbucks and zebras. The oryx is a gentle herbivore, surviving on grass and leaves, and spending much of its time dodging predators, such as big cats.

Samburu Serena nature expert Vincent Kapeen says that the lion who killed the first baby oryx may have mistaken the calf for a rival's cub — a common act of violence among lions — only later realizing it was a meal.

Another animal expert explained that perhaps the lioness had adopted the oryx because it did not display the classic "prey" behavior. Like many other predators, the lion has a complex hunting pattern, stalking, chasing and catching its prey before administering the "kiss of death," in which the big cat bites the other animal's muzzle, suffocating it to death.

But depending on the situation, experts say, the predator needs the prey to flee before its own hunting instincts are evoked. Some here say that perhaps the oryx, too young to flee and bearing the same golden tan coloring of a lion cub, evoked a maternal rather than hunting instinct in the lioness. On the oryx's part, the herd lifestyle dictates that young animals will always follow their mother or group, which could explain why the youngster stays so close to the lioness at all times.