Why Woodpeckers Never Get a Concussion啄木鸟为什么不会得脑震荡？

A strong hit to the head will normally give you a concussion. Woodpeckers， however， strike their beaks into trees thousands of times a day and are perfectly fine.

We used to think that a woodpeckers skull worked as a kind of safety helmet which absorbed the shocks. A study by Sam Van Wassenbergh， a researcher at the University of Antwerp in Belgium， proved that this “common sense” was in fact false.

Van Wassenbergh and his colleagues argued that， if a woodpeckers head absorbed the force， it would not be able to strike the tree with enough force.

“If the beak absorbed much of its own impact， the unfortunate bird would have to pound even harder，” they said in their paper. In other words， if the theory were true， the woodpecker would have to peck even harder to compensate for both the shock-absorbing qualities of the sponge-like bone inside its skull as well as the density of the wood.

頭部受到重击通常会造成脑震荡。然而，啄木鸟每天用喙啄树上千遍，却仍安然无恙。

我们过去认为啄木鸟的头骨像是某种安全头盔，可以吸收冲击。比利时安特卫普大学的研究人员山姆·范·瓦森伯格发布了一项研究，证明这种“普遍看法”实际上是错误的。

范·瓦森伯格及其同事认为，如果啄木鸟靠头部吸收了撞击带来的冲击力，那么它就无法以足够的力道啄树。

范·瓦森伯格团队在论文中写到：“如果啄木鸟通过喙吸收了大部分对自己的冲击力，那么这只不幸的鸟将不得不更加用力地撞击。”换句话说，如果“安全头盔”理论是正确的，受啄木鸟头骨内海绵状骨头减震特性和木材密度的影响，啄木鸟将不得不更加用力啄树去补偿缓冲掉的力。

The scientists recorded four different kinds of woodpeckers in zoos as they were pecking. The team used data from their high-speed recordings to build digital models of the woodpeckers. Van Wassenbergh described the woodpeckers motion as “a hammer hitting wood” since their movement appeared rigid and focused.

The research suggested that woodpeckers dont have any shock-absorbing device or the ability to reduce the amount of force. Although they are without “helmets”， the team claimed that the woodpeckers tiny size and weight protect them.

A woodpeckers brain is about 700 times smaller than that of a human. “Smaller animals can withstand higher decelerations. Think about a fly that hits a window and then just flies back again，” Van Wassenbergh said. “So that is why even the hardest hits we observed are not expected to cause any concussion.”

研究人员记录下动物园里四种不同啄木鸟啄食的情景，利用高速视频的数据，建立起啄木鸟的数字模型。因为啄木鸟的动作看起来僵硬而专注，范·瓦森伯格将其描述为“锤子凿木头”。

研究表明，啄木鸟没有任何减震器和减少冲击力的能力。不过研究团队表示，啄木鸟虽然没有“头盔”，但它们微小的体型和较轻的体重对自身起到了保护作用。

啄木鸟的大脑比人类的大脑小约700倍。“较小的动物可以承受较高的减速。试想一只苍蝇撞到窗户，然后又飞了回来。”范·瓦森伯格说，“所以，这就是哪怕我们观察到的最严重的撞击，也不会给啄木鸟造成任何脑震荡的原因。”

Word Bank

skull /sk?l/ n. 颅骨；头（盖）骨

pound /pa?nd/ v. 连续砰砰地猛击

She pounded him with her fists.

density /'dens?ti/ n. 密度

claim /kle?m/ v. 宣称；声称；断言

I dont claim to be an expert.

withstand /w??'st?nd/ v. 承受；经受住

The walls can withstand high winds.