Nature, it is said, abhors a vacuum. If humans were to disappear, could another species evolve into a tool-making, crop-raising, language-using beast that would dominate the planet? According to Alan Weisman, baboons might have a reasonable shot. They have the largest brains of any primate besides Homo sapiens, and like us they adapted to living in savannas as forest habitats in Africa shrank. Writes Weisman in The World without Us: “If the dominant ungulates of the savanna—cattle—disappear, wildebeest will expand to take their place. If humans vanish, will baboons move into ours? Has their cranial capacity lain suppressed during the Holocene because we got the jump on them, being first out of the trees? With us no longer in their way, will their mental potential surge to the occasion and push them into a sudden, punctuated evolutionary scramble into every cranny of our vacant niche?”
Hollywood, with its long series of Planet of the Apes movies, seems to agree with Weisman. A second out-of-Africa scenario could play out hundreds of thousands of years after the first. One wonders what the baboon archaeologists of the future would make of the extraordinary human artifacts—sculptures, cutlery, plastic bags—buried just beneath their feet. Weisman guesses that “the intellectual development of whatever creature digs them up might be kicked abruptly to a higher evolutionary plane by the discovery of ready-made tools.” Even as ghosts, we could continue to shape the future.