Calling someone a “birdbrain” is considered rude. It implies that someone has a small brain and thus

Calling someone a “birdbrain” is considered rude. It implies that someone has a small brain and thus is not smart. A new study found that the expression doesn’t do birds justice either. Birds’ brains are much bigger than we thought-at least compared to their small bodies.
An international team of 37 scientists measured the brain volume of hundreds of dinosaurs and extinct birds by scanning fossils of their skulls. The readings were compared to a large database containing the brain sizes of modern birds. These measurements were then analyzed, taking into consideration each bird’s body size-resulting in something called “relative brain size”. The results showed that a dramatic change of birds’ body size happened right after the mass extinction of dinosaurs 66 million years ago.
According to the study, published on April 23 in the journal Current Biology, birds and non-avian (非鸟类的) dinosaurs had similar brain sizes before the extinction. After the extinction of the dinosaurs, however, birds had to find a way to survive, so they shrank their bodies-since smaller animals need less food-but they kept their big brains.
“The changed landscape may have caused the rapid evolution of new brain-body scaling patterns (缩放比例) by favoring both larger brains and smaller bodies,” US paleontologist (古生物学家) Daniel Ksepka, who is the lead author of the study, told CNN.
This “evolutionary brain leap”-as scientists call it-also happened very rapidly. Without dinosaurs, birds quickly repopulated. They came in all types and sizes, which contributed to the diverse species of birds we see today.
But among all the bird species, certain ones “show above average rates of brain and body size evolution”, study co-author Adam Smith at Clemson University, US, said in a statement-with crows and parrots being the most evident. In fact, previous studies have already discovered that these birds have an amazing cognitive ability. They are able to use tools, imitate human speech and even remember human faces.
So, in the words of Smith, “calling someone ‘bird-brained’ is actually quite a compliment!”
12. How did scientists learn the brain sizes of dinosaurs and extinct birds?
A. By referring to a database.
B. By analyzing their body size.
C. By studying their fossil skulls.
D. By examining the brain size of modem birds.
13. What were birds’ brains like after the extinction of the dinosaurs?
A. They were the same size as non-avian dinosaurs.
B. They shrank to adapt to the environment.
C. They kept growing to avoid extinction.
D. They remained as big as they were before.
14. According to Adam Smith, what do we know about birds?
A. Their brain evolution happened very rapidly.
B. Some species evolved to be smarter than others.
C. Crows and parrots have the largest bird brains.
D. Birds have amazing abilities to copy human speech.
15. What is the purpose of this text?
A. To explain the origin of the word “birdbrain”.
B. To describe how a bird evolved through history.
C. To present a new study on birds’ brain size.
D. To reveal reasons for the rapid growth of bird populations.
【答案】