英语听力文摘 English Digest 683 狗狗嗅觉灵敏的原因

 

What Makes Dogs Such Great Sniffers?

Watch a dog greeting the world with its nose, or following invisible trails of scent¹, and you might wonder what you’re missing. In one study, dogs were able to smell a particular test scent a thousand times better than humans! What makes dogs such stupendous sniffers?

Smell Receptors

Like humans, dogs have special smell receptor cells lining² their noses. But dogs have about 20 times more of these cells than we do–and the differences don’t stop there!

From the receptor cells, information about smell travels along nerves to the olfactory³ bulbs, the parts of the brain where information about smell is processed. Relative to the size of its brain, a dog’s olfactory bulbs are much bigger than most other animals. If the animal kingdom held a sniffing⁴ Olympics, dogs and rats would probably battle for the gold, leaving the rest of us in the dust.

Tongue Transportation

Another advantage dogs have is that the schnoz isn’t the only tool they use for smelling. When a dog licks your hand, or something less savory⁵ found in the street, its tongue transports molecules⁶ from that surface into its mouth. Just above the roof of the dog’s mouth is the vomeronasal organ, which gathers information on smell from the molecules the tongue delivers. Humans have vomeronasal organs, too, but compared to dogs, ours are very rudimentary.

Although all dogs are stupendous sniffers, dogs bred for tracking such as beagles and bloodhounds are true professionals. There are also variations in individual dogs’ talents, and the dog’s diet and the type of scent all affect how well a dog can smell.

是什么让狗如此善于嗅嗅？

看着一只狗用鼻子向世界问好，或者沿着看不见的气味轨迹，你可能会想知道你错过了什么。在一项研究中，狗能够闻到比人类好一千倍的测试气味！是什么让狗成为如此惊人的嗅探器？

气味受体

和人类一样，狗的鼻子里也有特殊的嗅觉受体细胞。但狗的这些细胞数量是我们的20倍，而且差异并不止于此！

关于气味的信息从受体细胞沿着神经传递到嗅球，嗅球是大脑中处理气味信息的部分。相对于大脑的大小，狗的嗅球比大多数其他动物大得多。如果动物王国举办一届嗅嗅奥运会，狗和老鼠很可能会争夺金牌，让我们其他人都灰飞烟灭。

舌头运输

狗的另一个优点是，schnoz并不是它们用来闻气味的唯一工具。当狗舔你的手，或是在街上发现的不那么美味的东西时，它的舌头会把分子从表面输送到嘴里。就在狗的嘴顶上方是犁鼻器官，它从舌头传递的分子中收集关于气味的信息。人类也有犁鼻器官，但与狗相比，我们的犁鼻器官非常发育。

尽管所有的狗都是惊人的嗅探犬，但比格犬和猎犬等为追踪而饲养的狗才是真正的专业人士。个别狗的天赋也存在差异，狗的饮食和气味类型都会影响狗的嗅觉。

1 scent   

n.气味，香味，香水，线索，嗅觉；v.嗅，发觉

参考例句：

• The air was filled with the scent of lilac.空气中弥漫着丁香花的芬芳。
• The flowers give off a heady scent at night.这些花晚上散发出醉人的芳香。

2 lining   

n.衬里，衬料

参考例句：

• The lining of my coat is torn.我的外套衬里破了。
• Moss makes an attractive lining to wire baskets.用苔藓垫在铁丝篮里很漂亮。

3 olfactory   

adj.嗅觉的

参考例句：

• He is to develop a sensor to substitute for the olfactory abilities of dogs.克罗克将研制一种传感器用以代替狗的嗅觉功能。
• Based on these findings, Keller suspects that each person has an olfactory blind spot.根据这些发现，凯勒推断，每个人都有一个嗅觉盲区。

4 sniffing   

n.探查法v.以鼻吸气，嗅，闻( sniff的现在分词 )；抽鼻子（尤指哭泣、患感冒等时出声地用鼻子吸气）；抱怨，不以为然地说

参考例句：

• We all had colds and couldn't stop sniffing and sneezing. 我们都感冒了，一个劲地抽鼻子，打喷嚏。
• They all had colds and were sniffing and sneezing. 他们都伤风了，呼呼喘气而且打喷嚏。 来自《现代英汉综合大词典》

5 savory   

adj.风味极佳的，可口的，味香的

参考例句：

• She placed a huge dish before him of savory steaming meat.她将一大盘热气腾腾、美味可口的肉放在他面前。
• He doesn't have a very savory reputation.他的名誉不太好。

6 molecules   

分子( molecule的名词复数 )

参考例句：

• The structure of molecules can be seen under an electron microscope. 分子的结构可在电子显微镜下观察到。
• Inside the reactor the large molecules are cracked into smaller molecules. 在反应堆里，大分子裂变为小分子。