双击或划选（点我安装在线划词），即可查看单词的详细解释，并收录生词进 生词本

PETS
2007, August 31, Friday

The Truth About Cats and Dogs (2/2)
Interesting facts you never knew about your favorite pets

Q: Is it really true that when a dog's nose is cold and wet, it means she's healthy?

A: To really get to the bottom of this, we need to understand why a dog's nose is wet in the first place. Tears are constantly produced to lubricate the movement of the eyes. These excess tears flow through the naso-lacrimal (literally "nose-tears") duct and out the base of the nose. (People experience this when crying.)

As the tears drip down into the dog's face, the dog licks her nose, spreading the tear fluid over the nose, which wets it. The moistened nose is better equipped to dissolve airborne chemicals, which contributes to a better sense of smell.

When a dog is sick, the body uses up more internal water in the process of fighting disease. This increased use causes relative dehydration, even if the dog is drinking a normal amount of water. This results in decreased tear production, and hence a dry nose.

The bottom line is that the dry nose is one indicator of hydration, but it indicates illness only if it's coupled with lethargy and other symptoms.

Q: When dogs yawn, are they sleepy or bored?

A: Neither, really. Think of yawning as a kind of switching gears. A yawn increases the flow of oxygen and boosts the heart rate.

Dogs yawn both to charge themselves up and to calm themselves down. It depends on the situation. If you go to a canine agility competition, you'll often spot dogs yawning at the starting line while waiting for the signal to race across the line to the first obstacle. They're ready to run, and the yawn expresses that stress and excitement. In the waiting room of a veterinary hospital, you'll often see dogs yawning, too-a sure sign that they're stressed and trying to calm themselves.

Vocabulary Focus

lubricate (v) ---to apply a substance that makes movement easier

airborne (adj) ---relating to something carried by air or wind

agility (n) ---the ability to move your body quickly and easily

Specialized Terms

dehydration (n) ---脱水the condition of not having enough water in the body

lethargy (n) ---疲惫the feeling of being tired and having no energy