揭祕：汪星人爲嘛要搖尾巴
You're at a friend's house and along comes her collie, Baby, wagging her tail. Good girl! You bend over to pat her and are rewarded with a growl. What went wrong?
你去到朋友家，她的牧羊犬小寶搖着尾巴迎了上來。真乖！你彎下身子拍拍她的頭，她卻對你低吼了一聲。哪裏不對勁了？
"It is so important for people to realize that a wagging tail does not equal a dog that is friendly or wants to be petted," says E'Lise Christensen Bell, veterinarian and board certified veterinary behaviorist at Veterinary Behavior Consultations of NYC. "It can, but you are much better off looking at the entire dog. If there are stiffened muscles, dilated pupils, tense facial muscles, or ears pinned forward or back, these are signs that you should back off."
“人們應該要知道，狗搖尾巴不等於示好，也不一定是想要和你親暱，”獸醫兼紐約動物行爲協商會的認證動物行爲學家艾麗絲·克莉絲汀森·貝爾說道。“搖尾巴可以表示友好，但是最好還是整體地看。如果它肌肉僵硬、瞳孔放大、面部緊繃、耳朵或前或後緊貼着頭，你就最好離它遠一點。”
For help with figuring out what the tail wag means, look for the direction of the wag or at how fast his tail is moving. Studies show that dogs wag their tails to the right when they are happy and to the left when they are frightened.
觀察尾巴搖的方向或者速度也可以幫助你解讀搖尾巴的含義。研究顯示狗在高興的時候尾巴會往右擺，害怕的時候會往左擺。
If Baby wags her tail high and back and forth, she's in her "happy place". When she's just being plain nosy, she will keep her tail horizontal to the ground. When Baby's tail is tucked between her hind legs, she's either frightened or being submissive. When she's wagging it low, she's worried or feeling insecure about something.
如果小寶尾巴搖得高高地還前後晃，她就是高興的。如果她只是好奇，她的尾巴會跟地面保持水平。如果小寶的尾巴垂到了後腳，她要不就是被嚇到了，要不就是表示順從。如果她的尾巴搖得很低，她就是在擔心什麼，或者是沒有安全感。
Dogs wag their tails for other dogs, humans, and other animals like cats. But research shows that dogs don't wag their tails when they are alone because there is no need. Just as humans use smiles and body language as social cues in different situations, our canine friends do the same.
狗會對其它狗、人和其它動物（比如貓）搖尾巴。研究發現狗獨處的時候不會搖尾巴，因爲沒有必要。人類在各種的社交場合會用微笑和肢體語言表達情感，我們來自汪星的朋友也會這麼做。
"Dogs are much better at reading each other's body language than we are," says Dr. Bell. "Dogs that are behaving appropriately in social systems use their bodies and tails to communicate with other dogs even as they are observing the tails and body position of other dogs. This helps them avoid unnecessary conflicts."
“狗對肢體語言的解讀能力比我們強多了，”貝爾博士說。懂得正確社交禮儀的狗在觀察其它狗的尾巴和身體姿勢的同時就已經開始用身體和尾巴交流了。這能幫它們避免不必要的衝突。”
Dogs also wag their tails to spread their natural scent from their anal glands. Each dog has a scent that's unique to him or her. An "alpha" or dominant dog that carries his tail high will release more of his scent than a dog that carries his tail lower. Often, when we see a dog holding his tail between his legs, he's frightened and doesn't want to release his scent. This is his way of flying under the radar.
狗還會通過搖尾巴來散發肛門腺的氣味。每一隻狗都有獨一無二的氣味。強勢的狗會把尾巴伸得很高，這樣就會比尾巴放得低的狗釋放更多的氣味。通常我們看到尾巴垂到兩腿之間的狗都是被嚇到了，所以不想散發出自己的氣味。這是他們隱藏自己的方法。
Since dogs haven't yet figured out a way to talk to their owners and their other animal cohorts, they have to use their bodies to communicate. The eyes, ears and body positions are a few clear indicators of how they feel. But wagging their tails is one of the most visible and well-known ways canines use to clue people and other animals in on exactly what's going on with them.
狗現在還沒有找到跟主人和其它動物說話的方法，所以它們得用身體交流。犬科動物的眼睛、耳朵和身體姿勢都能清楚地反映它們的心情，但對人類和其它動物來說，搖尾巴是最容易看見、最被熟知的方式。
