久久亚洲国产成人影院-久久亚洲国产的中文-久久亚洲国产高清-久久亚洲国产精品-亚洲图片偷拍自拍-亚洲图色视频

您現(xiàn)在的位置: > Language Tips > Easy English > Odd Question  
 





  Why do deer shed their antlers?
[ 2006-02-21 08:07 ]

   
  Deer
   
  Why do deer shed their antlers?
Deer shed their antlers annually as a prelude to the regeneration, or re-growth, of new ones.

The entire shedding process takes a mere two to three weeks to complete, and the re-growth phase takes place over the summer. The docile male deer that, with the exception of the male and the female reindeer, solely sports antlers, sheds them between January and April, after the autumn mating season draws to a close. He can do without antlers at this time, because his need for them in prior months, to attract and to impress females for his harem of mates, and to fight with his competitors for the females' affections, no longer exists.

The antlers themselves differ from the hollow horns of cattle, in that they comprise solid bone tissue with a honey combed structure. Pedicles, or knobby, skin-covered nubs protruding from the skull, support the deer's antlers, or points, which range in number from one shaft to eleven branches. The pedicles are a permanent fixture on the deer's forehead, and are the point from which the antlers annually break off.

During the first year the pedicles appear on the young deer's forehead. The following year, the youngster sprouts straight, spike-like shafts, and in the third year, the first branch appears. In successive years, as the deer matures, his antlers lengthen and, in most species, he acquires additional branches. One can actually determine the age of the deer from the number of branches on his antlers, as their number increases with age.

During the growth phase of the bony antlers, they are covered with a sensitive skin referred to as "velvet“, which is filled with blood vessels that feed the antlers the vitamins and the minerals necessary to build up the bone, and to promote normal antler growth. Antler growth spans two to four months, after which time the velvet is no longer needed, and a ring, which effectively serves as a shutoff valve, forms at the base of the antlers and cuts off the blood supply to the velvet. As a result, the velvet withers, dries up, and falls off, often assisted by the deer, which rubs his antlers against tree bark. The antler regeneration is complete, and the shedding cycle will resume once mating season in the fall concludes.

 

note:

prelude: 前奏

 

 

 

docile: 溫順的


sport
: 炫耀,賣弄
mating: 交配
draw to a close: 漸近結(jié)束
harem: 一群雌動物

 


pedicle: 肉莖
knobby: 多節(jié)的
nub: 小塊

 

 

 

 

 

 


velvet: 天鵝絨

 
 
 




主站蜘蛛池模板: 国产精品久久久久毛片 | 德国女人一级毛片免费 | 免费人成观看在线网 | 久久99国产精品久久99无号码 | 久久999精品| 动漫精品一区二区 | 国产三级在线视频播放线 | 99精品高清视频一区二区 | 亚洲综合精品一区二区三区中文 | 中文字幕有码在线播放 | 真实国产乱人伦在线视频播放 | 天天se天天cao综合网蜜芽 | 成人免费毛片一区二区三区 | 全部精品孕妇色视频在线 | 亚洲精品综合一区二区三区 | 俄罗斯美女在线观看一区 | 国产黄色激情视频 | 亚洲三级网址 | 欧美一级美片在线观看免费 | 国产精品久久国产三级国不卡顿 | 成年片免费网址网站 | 97视频在线看 | 特级欧美视频aaaaaa | 97在线碰碰观看免费高清 | 欧美一级精品高清在线观看 | 欧美成人交tv免费观看 | 13一14周岁毛片免费 | 免费看黄色三级毛片 | 91在线精品亚洲一区二区 | a级片在线观看 | 免费国产一级 | 国产在线精品一区二区三区 | 又黄又骚| 久久综合久久美利坚合众国 | 在线观看日韩www视频免费 | 亚洲夜色夜色综合网站 | 国产原创91 | 麻豆md国产在线观看 | 亚洲成人在线免费 | 中国人免费观看高清在线观看二区 | 亚洲美女视频 |