Wearing a caveman mask, Dr. John Marzluff walks across the campus at the University of Washington in Seattle. Crows (乌鸦) circle and squawk (尖叫), diving at him and away.
Beneath the mask, he smiles. Days before, he and his students, wearing caveman masks, trapped them and placed colored plastic bands on their legs. Then they released the unhappy birds. When the researchers wandered around campus without the masks, the crows they had caught and banded did not react to them. But when the same humans walked by while wearing the masks, the crows scolded loudly and dived at their "enemies".
At first, only the banded birds reacted aggressively to the people in masks. But in later tests, more and more crows joined in, and even when the banded birds were not around. "Crows think and dream, fight and play, reason and take risks," he says. "Theiranticsconfuse us."
This led him to study how crows' brains work. He and his students wore one type of mask as they captured crows and brought them into the lab, training them to link that face with danger. Then a different kind of mask for more positive activities, such as feeding and caring. Then he worked with scientists at the university who scan animal brains to see which parts of a crow's brain do certain tasks. Surprisingly, the scientists found that when the crow saw the "danger" mask, one part of its brain became active. When the crow saw the "care and feeding" mask, a different part of its brain lit up. The team has shown that crows use the same parts of their brains for recognition that humans do — something that was not known before!
More than 10 years after the first mask experiment, campus crows still scold the "cavemen". Crows also recognize people who are kind to them. Crows are always watching us... and they remember.
