Ostriches1 live in Africa.They are the biggest birds in the world. They cannot fly， but they can run very fast.So what good are their big wings? Sometimes ostriches move their wings up and down to cool themselves. Other times they flap2 them to show off (炫耀，賣弄).

It is easy to tell male and female ostriches apart. Males are black with some fancy(別致的，花哨的) white feathers. Females are gray and brown.

A female ostrich， like the one below， becomes a male' s \"main hen(雌禽)\".The male mates (交配)with other hens too.Then he digs one nest in the sand. All of the hens lay their eggs in it. The male arm his main hen take turns sitting on the nest to keep the eggs warm. Art ostrich egg is bigger than a grapefruit(葡萄柚).

After about six weeks， the eggs begin to hatch， Baby ostriches are called chicks(小鳥).

Baby ostriches have spotted(有斑點的) necks and brown-gray bodies. Their markings(斑點、斑紋) blend3 in with the area around them. This helps the chicks hide from enemies.

Baby ostriches grow up fast. After their first day out of the egg， they can walk and feed themselves. In one year， they are as tall as their parents!A grown-up ostrich is about as tall as two children who are one metre high.

鴕鳥生活在非洲，是世界上最大的鳥，它們不能飛，但奔跑速度非?？臁Ｄ敲?，它們那巨大 的翅膀會有什么妙用呢？鴕鳥有的時候上下扇動翅膀來給自己降溫，還有的時候它們會拍打翅膀來炫耀自己。

雄鴕鳥和雌鴕鳥很容易區(qū)分，雄鴕鳥為黑色并長有一些漂亮的白色羽毛，而紫鴕鳥為灰色和棕色。

如下圖這只雌鴕鳥就是一只雄鴕鳥的“主要伴侶”。雄鴕鳥還會與其它雌鴕鳥交配。然后雄鴕鳥在沙地上挖個巢穴，它的雌性伴侶們都把蛋下在這個巢中。雄鴕鳥和它的主要伴侶輪流在巢穴上伏窩孵蛋以保持其溫度。一個鴕鳥蛋比一個葡萄柚還大。

大約6周以后，鴕鳥蛋開始孵化出來。幼小的鴕鳥被稱為幼雛。

幼小的鴕鳥脖子上有點狀花斑，身體為棕灰色。它們的斑紋和身邊的環(huán)境渾然一體，這樣有利于躲避天敵。

幼小的鴕鳥生長速度很快，從鉆出蛋殼的第一天起，它們就能行走和自己吃食。一年后就長得和父母一樣高了！一只成年鴕鳥大約有兩個1米高的兒童加起來那么高。

注釋：

1. ostrich n.[鳥]鴕鳥

2. flap vt.振（翅）

3. blend vi.混在一起，混和