Thorny Theory

A weapon for early man ?

The question has daunted anthropologists ever since 1871, when Charles Darwin grappled with it in his The Descent of Man. How did the puny early ancestor of modern man defend himself against predators? More than 3 1/2 million years ago, he stood only 120 cm to 140 cm (48 in. to 56 in.), too short to wield a heavy club effectively. For another million years or so, his brain was not developed enough to conceive of fashioning stone weapons. Yet despite the presence of far more powerful four-legged adversaries on the African savannas, he survived. Now a Dutch zoologist, Adriaan Kortlandt of the University of Amsterdam, has proposed an intriguing answer. In the current Journal of Human Evolution, he suggests that early man was able to use thorny branches to repel the most dangerous predators: large carnivorous cats.

The idea occurred to Kortlandt, 62, in 1976 on a dig in Ethiopia at a prehistoric site. Resting in the shade of a thorny acacia tree, he realized that a short bipedal creature could easily enough break off a branch covered with hooklike thorns, and wave it as a weapon; lions, Kortlandt knew, stay clear of thorns. To test his theory, he journeyed to the Kora National Reserve in Kenya and set large chunks of meat covered with thorn branches near a pride of twelve lions tamed by George Adamson of Born Free fame. The lions approached and batted tentatively at the branches, but refused to rip them away.

Next Kortlandt put a sheep in a wire-mesh cage surrounded by thorn branches. This time, several hungry lionesses began pulling at the branches. But when thorns became lodged in their paw pads, they retreated to lick their wounds. That suggested early man could have protected himself on the savanna by building thorn-branch shelters. But could he survive long sieges? To find out, Kortlandt attached branches to a remote-controlled motor on a framework over chunks of meat. When lions approached, the branches spun as they might had they been brandished by man. The lions darted away.

All of which raised another question:

Why are lions so wary of thorn branches? Kortlandt's theory: they seem like the flailing tails of animals that lions take great care to avoid--porcupines.

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