英语资讯
News

起跳后不懂着陆的青蛙

Source: 恒星英语学习网  Onion  2010-07-27  我要投稿   论坛   Favorite  

You’d think an animal that hops would know how to land. But for a kind of frog, that’s not the case. Imagine trying to catch a frog. You reach and they jump, only to land gracefully on their feet a few feet away.

It was thought that all frogs moved this way. They'd push off with their back legs, and then once in flight, rotate the limbs forward. Then they landed fore-limbs first. But researchers compared frogs of the family Leiopelmatidae, which still sport an ancient physiology, to two more modern frog species. Unlike their more graceful cousins, the primitive frogs kept their back legs straight out after they jumped. So they don’t land on their feet. Instead, they do an ungainly belly flop, and then struggle to get to their feet and jump again. The finding is in the journal Naturwissenschaften.

The scientists say that the back-leg push-off must have evolved first, with the ability to rotate and land softly evolving later. Although the bad landers are still around, their more controlled relatives appear to be better at making longer trips, foraging for food and, most importantly, avoiding other animals that have an interest in frog legs—for dinner.

—Cynthia Graber


将本页收藏到:
上一篇:瓶装水的罪恶
下一篇:一场针对B型肝炎的健康运动

最新更新
论坛精彩内容
网站地图 - 学习交流 - 恒星英语论坛 - 关于我们 - 广告服务 - 帮助中心 - 联系我们
Copyright ©2006-2007 www.Hxen.com All Rights Reserved