(单词翻译:单击)
听力文本
Study: Dogs Evolved to Use Eyes to Connect with Humans
Dog lovers are well aware of the ability of a dog to communicate with its eyes. Now, scientific research suggests this ability developed over time as dogs learned to live with humans.
Just like humans, the eyes can be one of the most appealing things about dogs, the animals known in many cultures as "man's best friend."
But a new study found evidence that dogs developed in physical ways to present "puppy dog eyes" as a way to help connect with humans. Researchers in Britain and the United States did the study. Results were published in the Proceedings of the National Academy of Sciences (PNAS).
The study compared the facial muscles of dogs and wolves, which share ancestral history. Dogs broke off from wolves after being domesticated about 33,000 years ago. During that time, dogs changed physically and behaviorally to fit life with humans.
The researchers examined the heads of six dogs and two wolves for comparison. They found the facial structure of both animals was mostly very similar. But one major difference was found above the eyes.
The dogs were found to have two well-formed muscles around the eye that were not present in the wolves. These small muscles permit dogs to "intensely" raise their inner eyebrow, the study found.
Anne Burrows is a professor at Duquesne University in Pittsburgh, Pennsylvania. She was a lead researcher on the study. "You don't typically see such muscle differences in species that are closely related," she told the Associated Press.
Comparative psychologist Juliane Kaminski from Britain's University of Portsmouth led the research. The team suggests this eyebrow-raising movement causes "a nurturing" feeling in humans because it makes the dogs' eyes appear larger.
This expression also makes the dog look more like a human baby. The eye movement is similar to that which humans make when they are sad, the statement said. "The evidence is compelling that dogs developed a muscle to raise the inner eyebrow after they were domesticated from wolves," Kaminski said.
In a separate part of the study, the researchers observed how 27 dogs and nine wolves interacted with a human. "We also studied dogs' and wolves' behavior. And when exposed to a human for two minutes, dogs raised their inner eyebrows more and at higher intensities than wolves," Kaminski said.
The researchers suggest that the eye movements developed over time as a way for dogs to get humans to do things for them. This could involve humans giving them food, care or attention.
Brian Hare, from America's Duke University, edited the study. He called the findings "profound" for showing that these muscles likely developed to help in their interactions with people. "The proof has been in their puppy dog eyes all this time," Hare said.
The only dog species in the study that did not have the muscles was the Siberian husky, which is an ancient kind. The husky could be the best living example of what the link between dogs and wolves looked like.
Anne Burrows said the main limitation of the study was the small number of dogs and wolves used. This means further study will be required and should include other ancient dog breeds. The work could also be extended to other animals with which humans have developed close relationships, including horses and cats, Burrows said.
I'm Bryan Lynn.
重点解析
重点讲解：
1. be aware of 知道的；明白的；
I'm always very aware of how much work there is still to be done.
我一直很清楚还要做多少工作。
2. break off 折断；（使）断开；
Grace broke off a large piece of the clay.
格雷斯掰下来一大块土。
3. be similar to 相像的；相仿的；类似的；
This is similar to waiting for a bus that never turns up.
这就跟等待一辆永远等不到的公共汽车差不多。
4. interact with 相互交流；相互沟通；
Even though I'm supposed to be working by myself, there are other people who I can interact with.
即便是需要我一个人工作，我还是可以和别人进行交流的。
参考译文
研究发现狗狗进化出了用眼神与人类交流的能力
爱狗一族非常清楚狗狗用眼神进行交流的能力。现在，科学研究指出，在狗狗学习与人类共同生活期间，这种能力也在随着时间的推移而不断发展。
和人类一样，眼睛可能是狗狗最吸引人的部位之一，许多文化都将狗狗看作“人类最好的朋友”。
但一项新研究发现了证据，能证明狗狗的身体进化出了惹人怜爱的眼神，以此来帮助它们和人类交流。这项研究由英国和美国的研究人员开展。研究结果发表在《美国国家科学院院刊》（简称PNAS）上。
这项研究将拥有共同祖先的狗和狼的面部肌肉进行了比较。大约3.3万年前，在被人类驯化后，狗从狼的血统中分离出来。其间，为了适应和人类共同生活，狗的身体和行为都发生了变化。
研究人员检查了6只狗和2只狼的头部，随后进行了对比。他们发现，这两种动物的面部结构极为相似。但他们发现的其中一个主要不同之处在于眼睛上部。
研究发现，狗的眼睛周围有完整的肌肉，但狼并没有。研究发现，这些小肌肉使狗狗能“大幅度”提高内眉。
安妮·巴罗斯是宾夕法尼亚州匹兹堡的杜肯大学的教授。她是这项研究的首席研究员。她对美联社表示，“通常，你不会在关系密切的物种之间看到这种肌肉差异。”
英国朴茨茅斯大学的比较心理学家朱利安·卡明斯基领导了这项研究。研究团队认为，这种抬眉动作会激发人类的“照顾欲”，因为这一动作令狗狗的眼睛看起来更大。
这种表情还使狗狗看上去更像人类婴儿。研究指出，抬眉动作类似于人类悲伤时的表情。卡明斯基表示，“这一证据充分证明，从狼驯化而成之后，狗逐渐进化出了抬起内眉的肌肉。”
在该研究的一个独立部分中，研究人员观察了27只狗和9只狼与人类的互动方式。卡明斯基说，“我们也研究了狗和狼的行为。在和人类接触的两分钟时间里，狗比狼更多、更强烈地竖起了内眉。”
研究人员认为，这种抬眉动作随着时间的推移演化而来，是狗狗让人们为它们做事的方法。这可能包括让人类给它们准备食物、照顾它们或关注它们。
美国杜克大学的布莱恩·黑尔编写了研究报告。他称研究结果“意义深远”，因为研究证明了狗狗进化出这些肌肉很可能是为了辅助它们与人类进行交流。黑尔表示，“一直以来，证据就在它们那惹人怜爱的眼神里。”
在这项研究中，唯一没有眼部肌肉的犬种是西伯利亚哈士奇犬，这是一个古老的犬种。西伯利亚哈士奇犬可能是狗与狼之间联系的最佳实例。
安妮·巴罗斯表示，这一研究的主要局限是参与研究的狗和狼数量较少。这意味着有必要进行深入研究，同时应将其他古代犬种纳入研究。巴罗斯说，研究工作可能延伸至与人类发展出密切关系的其他动物，比如马和猫等。
布莱恩·林恩报道。
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