If you give a chimp a crystal, she might not give it back.
Researchers learned this the hard way. They gave quartz, calcite and other types of crystals to chimpanzees in a rehabilitation center. The apes responded with great interest, and the researchers ended up needing to trade large amounts of bananas and yogurt to get back the largest crystal. Others were never retrieved.
The crystal chimp study, published on Wednesday in the journal Frontiers in Psychology, was an attempt to understand what about the shimmering minerals is so attractive to the apes’ closest cousins, us. It was led by Juan Manuel García-Ruiz, a crystallographer at Donostia International Physics Center in Spain.
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For the first experiment, the researchers used two pedestals that were installed in the chimps’ yards. On one, they placed a multifaceted quartz crystal that stood about a foot tall, and on the other, a sandstone rock of similar dimensions. (Dr. García-Ruiz named this experiment “The Monolith” inspired by the world-changing object in Stanley Kubrick’s “2001: A Space Odyssey.”)
The chimps went crystal cuckoo.
In one yard, they repeatedly approached the monolith until the alpha female, Manuela, wrenched it off its pedestal. After that, the crystal rarely left the troop’s sight, while they largely ignored the sandstone rock. One video shows a 50-year-old male chimp named Yvan carrying it while he climbs and eats cabbage, passing it between his hands and feet with great panache.
In the other yard, the experiment was cut short after a chimpanzee named Sandy immediately grabbed both items from their pedestals and brought them into the dormitories, where human caretakers don’t generally go.
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For the second experiment, researchers set out piles of pebbles in the gardens, with a few small crystals incorporated into each. The chimpanzees immediately sorted the crystals out of the piles.
Then they carried them in their mouths, turned them in the light and held them up to their eyes like old-timey prospectors. When the researchers eventually set up cameras inside the chimp dorms, they saw that Yvan was still gripping one as he prepared to relax in his hay nest. (The research team has been unable to find or retrieve many of these smaller crystals, Dr. García-Ruiz said.)
From the article:
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