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科学美国人60秒 SSS Weakest Piglets May Sneak Help from Strongest Siblings

时间:2017-03-06 06:44来源:互联网 提供网友:nan   字体: [ ]
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Human parents usually have one or sometimes two offspring at a time, and when babies get delivered we pour all our energy into child rearing. But other animals raise lots of babies at once. And the weaker individuals can be at a big disadvantage. If there's not enough food, for example, a mother bird might offer more to those chicks who are more likely to survive. Nature's a rough place.

But mammals like pigs can't selectively provision their offspring the way birds do, because all the babies nurse at the same time. And yet the strongest piglets still seem to have an edge. One hypothesis goes that the weaklings might not have sufficient energy to stimulate1 the mammary gland2 while they suckle, so they eventually starve from a lack of nutrition.

But it turns out that vigorous stimulation3 of one mammary gland can increase blood flow in neighboring glands4. So if a weakling was canny5 enough to position himself next to one of his strongest siblings6, he might get more milk than positioned elsewhere.

"I got this idea during observations of piglets, of course, because I had a feeling that weaklings are doing better in the company of [the] strongest siblings."

Biologist Janko Skok from Slovenia's University of Maribor.

To see if his hunch7 was right, Skok observed 18 litters, including 150 piglets. Twenty-three of them were classified as weaklings, which meant they weighed less than one kilogram at birth or they died before weaning. Then he looked to see what differentiated8 the weaklings that survived from those that died.

And indeed, those weaklings that survived were more likely to nurse next to their strongest brothers and sisters. "Weaklings, which are limited in terms of mammary gland stimulation, actually take advantage of strong stimulation implemented9 by their heavier siblings, who in turn do not suffer any costs from this activity."

The research were published in the journal Behavioural Processes. [Janko Skok, Being a weakling and surviving: Keep the fittest siblings close-by when eating.]

Skok says that pig breeders commonly sort piglets into different weight classes, so the heaviest babies nurse together with one mother while a different mother raises the weaker babies. But his results might mean that more piglets could survive if breeders instead mixed piglets of different sizes, so that the smaller ones could take advantage of their larger counterparts.

What this finding does not explain is why my younger brother, who as a kid always and failed to steal my dessert, is now stronger than I am.

—Jason G. Goldman


点击收听单词发音收听单词发音  

1 stimulate wuSwL     
vt.刺激,使兴奋;激励,使…振奋
参考例句:
  • Your encouragement will stimulate me to further efforts.你的鼓励会激发我进一步努力。
  • Success will stimulate the people for fresh efforts.成功能鼓舞人们去作新的努力。
2 gland qeGzu     
n.腺体,(机)密封压盖,填料盖
参考例句:
  • This is a snake's poison gland.这就是蛇的毒腺。
  • Her mother has an underactive adrenal gland.她的母亲肾上腺机能不全。
3 stimulation BuIwL     
n.刺激,激励,鼓舞
参考例句:
  • The playgroup provides plenty of stimulation for the children.幼儿游戏组给孩子很多启发。
  • You don't get any intellectual stimulation in this job.你不能从这份工作中获得任何智力启发。
4 glands 82573e247a54d4ca7619fbc1a5141d80     
n.腺( gland的名词复数 )
参考例句:
  • a snake's poison glands 蛇的毒腺
  • the sebaceous glands in the skin 皮脂腺
5 canny nsLzV     
adj.谨慎的,节俭的
参考例句:
  • He was far too canny to risk giving himself away.他非常谨慎,不会冒险暴露自己。
  • But I'm trying to be a little canny about it.但是我想对此谨慎一些。
6 siblings 709961e45d6808c7c9131573b3a8874b     
n.兄弟,姐妹( sibling的名词复数 )
参考例句:
  • A triplet sleeps amongst its two siblings. 一个三胞胎睡在其两个同胞之间。 来自《简明英汉词典》
  • She has no way of tracking the donor or her half-siblings down. 她没办法找到那个捐精者或她的兄弟姐妹。 来自时文部分
7 hunch CdVzZ     
n.预感,直觉
参考例句:
  • I have a hunch that he didn't really want to go.我有这么一种感觉,他并不真正想去。
  • I had a hunch that Susan and I would work well together.我有预感和苏珊共事会很融洽。
8 differentiated 83b7560ad714d20d3b302f7ddc7af15a     
区分,区别,辨别( differentiate的过去式和过去分词 ); 区别对待; 表明…间的差别,构成…间差别的特征
参考例句:
  • The development of mouse kidney tubules requires two kinds of differentiated cells. 小鼠肾小管的发育需要有两种分化的细胞。
  • In this enlargement, barley, alfalfa, and sugar beets can be differentiated. 在这张放大的照片上,大麦,苜蓿和甜菜都能被区分开。
9 implemented a0211e5272f6fc75ac06e2d62558aff0     
v.实现( implement的过去式和过去分词 );执行;贯彻;使生效
参考例句:
  • This agreement, if not implemented, is a mere scrap of paper. 这个协定如不执行只不过是一纸空文。 来自《现代汉英综合大词典》
  • The economy is in danger of collapse unless far-reaching reforms are implemented. 如果不实施影响深远的改革,经济就面临崩溃的危险。 来自辞典例句
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TAG标签:   科学美国人60秒  英语听力  sss
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