1 . In the late 1970s, archaeologists (考古学家) uncovered the remains of a woman and a young dog, her hand resting on the puppy’s chest in a 12,000-year-old village.
The find is some of the earliest evidence of the bond between humans and dogs. But even after years of study researchers are divided on how this bond began. Did it arise over thousands of years, as early dogs became tamer (驯服的) and more accustomed to human behaviors? Or was this fire already burning in the ancestors of dogs: the gray wolf?
Christina Hansen Wheat, a behavioral ecologist at Stockholm University, and workmates hand-raised 10 gray wolves from the time they were 10 days old. When the animals were 23 weeks old, a caregiver led them one at a time into a mostly empty room. Over the course of several minutes, the caregiver exited and entered the room, sometimes leaving the wolf alone, sometimes leaving it with a complete stranger. The team repeated the experiment with 12 23-week-old Alaskan huskies (哈士奇), which they’d raised similarly since puppyhood.
For the most part, the scientists saw few differences between the wolves and the dogs. When their caregiver entered the room, both species scored 4.6 on a five-point scale of “greeting behavior”—a desire to be around the human. When the stranger entered, dog greeting behavior dropped to 4.2 and wolf to 3.5, on average, suggesting both animals made a distinction between the person they knew and the one they didn’t. It’s this distinction that the team counts as a sign of attachment.
In addition, dogs barely paced—a sign of stress—during the test, while wolves paced at least part of the time. However, the wolves stopped pacing almost entirely when a stranger left the room and their caretaker returned. Hansen Wheat says that’s never been seen before in wolves. It could be a sign, she says, that the animals view the humans who raised them as a “social buffer”.
For her, that’s the most interesting part of the study. “If this is true, this sort of attachment is not what separates dogs from wolves,” she says. In other words, it didn’t have to be bred into them by humans, but could have been the seed we selected for, and then strengthened over thousands of years.
1. What’s the purpose of Hansen Wheat’s experiment?
| A．To find out what makes gray wolves and dogs different. |
| B．To explain the reasons why humans raised dogs from ancient times. |
| C．To argue gray wolves after being tamed are easier to keep than dogs. |
| D．To prove whether gray wolves can make doglike attachment to people. |
2. What do we know about Hansen Wheat’s experiment from paragraph 3 and 4?
| A．Researchers began to raise gray wolves from their birth. |
| B．Researchers used equal numbers of gray wolves and dogs. |
| C．Gray wolves felt more stressful than dogs when a stranger came. |
| D．“Greeting behavior” of the two animals was significantly different. |
3. What do the underlined words “social buffer” in paragraph 5 mean?
| A．A reminder of feeding. | B．A sign of social attachment. |
| C．A source of comfort and support. | D．A warning of stopping pace. |
4. What will Hansen Wheat probably agree with according to the last paragraph?
| A．Dogs are more attached to humans than gray wolves. |
| B．It is the attachment to humans that sets gray wolves apart from dogs. |
| C．The attachment between dogs and humans is the result of being tamed. |
| D．The attachment to humans plays a role in the choice of dogs or gray wolves. |
