A new study shows that chimpanzees share humans' attraction to crystals, suggesting the behavior dates back at least six million years. Researchers found that the animals preferred crystals over ordinary stones and examined them closely.
Archaeologists have found crystals at ancient sites with Homo remains dating back 780,000 years. These stones showed no signs of use as tools or ornaments, raising questions about their appeal.
Scientists at the Rainfer Foundation in Spain tested this interest with enculturated chimpanzees. The animals quickly selected crystals from piles of pebbles and studied their transparency and shape for hours.
Lead author Prof Juan Manuel García-Ruiz said the chimpanzees' response was strong and natural. One chimp named Sandy even sorted crystals from pebbles and carried them away.
The findings point to transparency and geometric form as key factors. García-Ruiz concluded that sensitivity to crystals has deep evolutionary origins shared with humans.