狗_900字

　　Dogs belong to the canine.

　　When a dog follows its nose,its actually being led by thee key senses.Sight:a glimpse of the enemy saves them barking up the wrong tree.Sound:a bark can be a fierce threat,but its also how canines make their long distance calls.Smell:this tells a dog more than all the other senses put together.

　　Inside its nose are around two hundred million smell sensitive cells,forty times more than in humans.Through them the dogs brain can pick up signals from one molecule of scent in a million.It gives the dog:a completely different picture of the world,based on what it smells,rather than what it sees.

　　Flowers are irrelevant to a dog.So their scent is meaningless.But food is a serious matter.What to us is an empty plate,is covered with the smell of chicken to a hungry dog.

　　狗属于犬科劝物.

　　当狗用鼻子嗅着前行时,实际上有三种感觉在起作用：视觉,瞥一眼就知道敌人在哪儿；听觉,犬吠有一种凶猛的威慑力,这也是犬科动物闽相互嗅寻的方式；嗅觉,能给狗提供的信息比其他感觉总和还多.

　　狗的鼻孔大约有2亿左右的嗅觉细胞——比人多40倍.通过这些细胞,它的大脑能从100万个气体分子中筛选出1个.根据所闻而不是所见的东西,展现给狗的是一个完全不同的画面.

　　花对狗来讲无足轻重,所以花香对狗无关紧要.可食物是件大事,对我们来说是一个空盘子,可对一只饥肠辘辘的`狗来说却散发着鸡肉的香味.

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