For nearly every step of his almost 12-mile walk, Darryl Dyer has company. Flocks of crows follow him, signaling each other, because they all know that he’s the guy with the peanuts.
“They know your body type. The way you walk,” Dyer said. “They’ll take their young down and say: ‘You want to get to know this guy. He’s got the food.”
Scientists for years have known that crows have great memories, that they can recognize a human face and behavior, and can pass that information onto their babies.
Nowadays, researchers are trying to understand more about the crow’s brain and behavior, specifically what it does when the birds see one of their own die. They react loudly to the dead, but the reasons aren’t entirely known. Among the guesses is that they are mourning; losing a partner could be a significant moment for the social animals. Crows place sticks and other objects on dead birds—a funeral of sorts.
“Crows have evolved to have these complex social relationships, and they have a big brain,” said Kaeli Swift, who led the study.
How big of a brain? Crows are on par with smart mammals, like dolphins and monkeys, in brain-to-body proportion (比例). They have been known to be problem solvers and are among the few animals recorded to use tools.
In another part of the experiment, using slightly radioactive tracers, researchers measured the brain activity of crows after they were shown a dead bird. The scans showed the section of the hippocampus-the part involved in memory formation-light up at the sight of death. “In that particular situation at least, that crow was learning about a place, or a face, or a situation and associated it with that dead crow,” said Johin Marzluff, the lead researcher.
8. What does Darryl Dyer say about the crows?
A.They have good teamwork. |
B.They want to get to know him. |
C.They like peanuts best. |
D.They are familiar with him. |
9. What can be learned from the text?
A.Crows behave badly to each other. |
B.Crows can’t remember things well. |
C.Crows can acquire information from their parents. |
D.Crows mourn their partners’ death in a silent way. |
10. Which of the following can replace the underlined phrase “on par with” in Paragraph 6?
A.the same as |
B.different from |
C.related to |
D.opposite to |
11. What is the best title for the text?
A.Crows Are Friends of Humans |
B.A Big Brain Makes Crows Intelligent |
C.Crows Can Memorize Things |
D.Crows Hold-a Funeral for the Dead |