Dogs bark， cats meow， birds chirp. We're pretty familiar with these forms of communication. But animals use sounds in other ways too. To find a mate， the male ruffed grouse1 stands on a hollow log and beats his wings， making a drumming sound. The hollow log amplifies the sound so that it can be heard for up to a quarter of a mile. Mole rats use a banging sound for the opposite reason. They like to live alone， so they warn other mole rats to stay out of their way by banging their heads on the top of their tunnels.
     Sometimes making the right sound can be a matter of life and death. With some spiders， including the black widow， the male is much smaller than the female. When the male wants to approach a female to mate， he climbs onto her web and then steps carefully to vibrate2 the web in a certain pattern. This vibration tells the female： “I'm not dinner. I'm one of your kind.”
     Anyone who has used a dog whistle knows that dogs can hear sounds pitched so high that humans can't hear them. Other animals， such as cats， bats， moles， hedgehogs3， and dolphins， can also hear high-pitched sounds， or ultrasounds4.
     Animals use touch to communicate in many ways. Biting， kicking， and hitting send obvious messages， but touch can also be used in friendly ways. Chimpanzees5 will touch hands to greet each other. Many primates6 groom7 each other as a way to show friendship， removing bits of dirt or insects from each other's fur. Elephants touch trunks in greeting.
     Elephants also use their trunks for signals. A baby elephant will raise its trunk in the air when it wants attention from its mother. Body language is important to other creatures， too. When a gorilla is startled， it may stand still and shake its head back and forth. This means it does not intend to harm you. A chimpanzee will wear a special “play face” when it wants to let you know it's friendly.
     Some creatures even put their message in lights. Each type of firefly has its own flashing code. This helps males and females find mates of the same species. The lights not only tell what kind of firefly it is， they also guide the insects to each other. Color can also be important. The cuttlefish turns different colors to show how it feels. When it's ready to fight， it turns a dark color. Its colors change quickly when it is agitated8.
     Some bears and tigers leave visual signs. They put scratch marks on a tree as high up as they can. When another bear or tiger comes along， it may discover it can't make marks that high. That tells the visiting animal that the tiger or bear that made the marks is bigger and should be left alone.
     Another way to communicate without actually being there is through smell. A gazelle has special scent glands9 near its eyes that it rubs on branches to mark its territory. When other gazelles10 pick up the smell， they realize that this territory has already been claimed. Many animals mark territory by smell， including domestic cats and their wild cousins.
     聲音
     狗兒汪汪，貓咪喵喵，小鳥啾啾，這是我們再熟悉不過的交流方式了。不過動物們的這些聲音還別有用處。雄松雞在求偶的時候總是站在空心的圓木上拍動翅膀，發(fā)出擊鼓般的聲音?？招牡哪绢^可以將聲音放大，傳到周圍0.25英里遠(yuǎn)的地方。而鼴鼠發(fā)出砰砰的聲音，其目的則剛好相反。因為它們喜歡獨居，所以它們通過用頭部撞擊自己所在的洞穴上方告誡其他鼴鼠走遠(yuǎn)點。
     有時候能否發(fā)出正確的聲音是一件事關(guān)生死的事情。在某些蜘蛛群里——例如“黑寡婦”蜘蛛——雄蜘蛛的個頭要比雌蜘蛛小得多。在雄蜘蛛需要與雌蜘蛛交配的時候，它會爬到雌蜘蛛的網(wǎng)上，小心地踩住，用一種特定的方式晃動蛛網(wǎng)。這樣就等于告訴后者：“我不是什么大餐，我是你的同類！”
     如果有誰用過狗哨，那他一定知道狗能夠聽到音調(diào)很高的聲音，而人卻辦不到。其他動物如貓、蝙蝠、鼴鼠、刺猬和海豚也能夠聽到高音調(diào)的聲音或者是超聲波。
     觸摸
     動物們也可以通過觸摸進行多種交流。撕咬和踢打都可以發(fā)出很明顯的信息，但是觸摸也是一種友好的方式。黑猩猩就是通過觸摸對方的手互致問候的。很多靈長類動物表達(dá)友誼的一種方式是為對方清除身體上的污垢和虱子，以將毛皮弄干凈。大象們則通過碰鼻子來表達(dá)問候。
     目視
     大象也用鼻子來發(fā)信號。象寶寶如果想要引起象媽媽的注意，它會把它的鼻子高高舉起。身體語言對于其他的動物同樣重要。要是一只大猩猩受到了驚嚇，它會站著不動，同時來回不停地?fù)u晃它的腦袋，表示它并無惡意。而黑猩猩在表示友好的時候，它臉上會顯現(xiàn)出一副特殊的“滑稽”表情。
     有些動物則通過發(fā)出光來傳遞信息。每一種螢火蟲都有自己的發(fā)光代碼，這樣可以幫助它們在同類中求偶。所發(fā)出的光不僅有助于辨別種類，還能起到相互引導(dǎo)的作用。顏色的作用也舉足輕重。墨魚會通過變色來表達(dá)自身的感受。當(dāng)它準(zhǔn)備要大打出手時，它會變成黑色。激動時，它們的顏色則變化得非常快。
     某些熊和老虎會留下明顯的標(biāo)志。它們一般都在樹上盡可能高的地方留下爪印。當(dāng)其他的熊或者老虎想要尾隨而來時，它可能發(fā)現(xiàn)無法在更高的地方印下印記。這就意味著爪印高的熊或老虎體形比自己要大，不要去招惹它。
     氣味
     另外一種不需要面對面交流的方式是通過氣味進行的。瞪羚的眼部附近有特殊的臭腺。它們用這個部位不斷摩擦樹枝，以此標(biāo)明自己的領(lǐng)地。其他的瞪羚嗅到這種氣味后，它們就會明白此地已有歸屬。許多動物就是用氣味畫地為牢的，這其中包括家貓和野貓。