D

Elephants are social animals. They live with their families, give hugs and call each other by using their trunks (象鼻) as trumpets. They also might know how to help each other.

In a recent elephant study by researchers from the United States and Thailand, pairs of huge animals learned to cooperate (work together) to get some ears of corn. Perhaps the finding is not too surprising: scientists suppose that elephants may be among the smartest animals on the planet.

Joshua Plotnik, who worked on the study, told Science News that the animals didn‘t just learn a trick (诀窍). Instead, the ways the elephants behaved show that they understand how working together brings benefits to everyone.

To work out whether elephants can cooperate, Plotnik and Frans de Waal, a comparative psychologist at Emory University in Atlanta, built a test. The test was based on one that‘s been used to study the behavior of primates (灵长类动物) for more than 70 years.

In the case (案例) of elephants, they were trying to get to some delicious corn sitting on a stage. The rope ran around the stage. Animals received corn treats only if both pulled the rope ends at the same time with their trunks. This cooperation brought the stage close enough for them to reach the corn with their trunks.

The scientists studied six elephants at the Thai Elephant Conservation Center in Lampang, Thailand. The elephants worked out how to get the corn, but Plotnik and his co-workers wanted to know if the animals had simply learned a trick, or if they understood some basic ideas about cooperation. So the researchers did more experiments. In one, a single elephant was led to the rope and stood, alone, waiting. The animal waited patiently for more than 25 seconds for another elephant to come along — the animals seemed to know that sometimes, you have to wait for help to get the job done.

Sometimes an elephant waited as long as 45 seconds. ―That‘s a long time for an animal waiting for food,‖ Plotnik told Science News.

So far, only elephants and primates have successfully cooperated to master this kind of pull-together test. But that doesn‘t necessarily mean other animals don‘t cooperate. Plotnik says many behaviors in the animal kingdom may be explained by cooperation, but perhaps human scientists don‘t understand the rules. Experiments like the simple pull-together test give scientists a way to begin to learn.

56. Which of the following is true about elephants?

A. They use their trunks as trumpets for fun.

B. They probably know how to help others.

C. They play with other animal families.

D. They like eating ears of corn best.

57. Why does the writer talk about the case of elephants?

A. To explain why elephants are among the smartest animals.

B. To tell us that elephants are patient enough to get the food.

C. To show us how the experiments on elephants were organized.

D. To suggest that elephants have some basic ideas of cooperation.

58. What can we know from the passage?

A. Many animals‘ behaviors are related to cooperation.

B. Some scientists have found animals‘ rules of cooperation.

C. Moststudies can prove the reason why animals cooperate.

D. More experiments are needed to help know about cooperation.

59. What might be the best title for the passage?

A. Think of ―You‖ in Working     B. A Way to Begin to Learn

C. There‘s No ‘I’ in Elephant       D. No Match for Elephant