ADM-201 dump PMP dumps pdf SSCP exam materials CBAP exam sample questions

锤头鲨之谜 – 译学馆
未登陆,请登陆后再发表信息
最新评论 (0)
播放视频

锤头鲨之谜

Hammerhead Shark Mystery | JONATHAN BIRD'S BLUE WORLD

今天 跟随乔纳森探索斜着游泳的鲨鱼
Today, Jonathan investigates sharks that tiltwhen they swim!
欢迎来到乔纳森·伯德的蔚蓝世界
Welcome to Jonathan Bird’s Blue World!
水下世界充满了待人探究的奥秘
The underwater world is full of mysteriesto be solved.
其中一个就与锤头鲨(双髻鲨)有关
One such mystery involves the Great Hammerheadshark.
潜水员们极少看到过它们
Divers rarely see Great Hammerheads.
它们被看作是害羞的独行侠
They are known for being shy loners,
不愿接近人类
unwilling to approach people.
但几年前
But a few years ago,
潜水员们开始光顾
divers began visiting a place near
巴哈马的靠近比米尼岛的一片水域
Bimini Island in the Bahamas,
在那里 渔民捕猎锤头鲨已有些年头了
where Great Hammerheads have been caught byfishermen for years.
他们找到了一块鲨鱼遍布的特殊区域
They found a special place with lots of sharks.
随着时间的推移 鲨鱼习惯了潜水员的存在
Over time, the sharks got used to divers
并开始为了零食而靠近人们
and started coming in close for a snack,
人们也得以更近距离地观察它们
giving people an intimate look at the Great Hammerhead shark.
我来过比米尼岛数次 并且
I have been to Bimini several times and
总是惊诧于锤头鲨的巨大个头
I am always amazed by how huge Great Hammerheads are.
不仅是头部能长到一米多宽
Not only does the head reach a meter or more wide,
其高高的背鳍也是
but the tall dorsal fin is
这种独特而又宏伟的鲨鱼的显著特征
a striking feature of this unique and majestic shark.
尽管有着凶悍的外表
And in spite of the aggressive appearance,
锤头鲨几乎从不攻击人类
Great Hammerheads almost never attack people.
它们更喜欢藏在沙子里的黄貂鱼
They much prefer to eat stingrays in the sand.
但与锤头鲨共潜
But diving with Great Hammerheads has
让潜水员们注意到了不寻常的事
allowed divers to notice something unusual—
这种大鱼常常以一定角度斜向一边地游
the shark often swims tilted to the side at an angle.
我在乔治亚水族馆的海洋旅行者展区也注意到了这点
I also noticed this behavior in the Ocean Voyager Exhibit at the Georgia Aquarium.
我的朋友安迪·卡萨格兰德——
My friend Andy Casagrande—
探索频道的鲨鱼周节目的主要摄影师之一——
one of Discover Channel’s primary Shark Week cinematographers—
想帮我们解开锤头鲨身上的斜泳之谜
wanted to help investigate the mystery of the leaning Hammerhead.
他将一个GoPro相机固定到
He attached a GoPro camera
一头锤头鲨的大背鳍上
to the huge dorsal fin of a Great Hammerhead,
对鲨鱼进行一段长时间的拍摄
to film the shark for an extended period of time.
这段惊人的连续镜头清晰地展现了
His amazing footage shed light on the behavior
鲨鱼的行为……它们的身体结构与之息息相关
of these sharks…and it has to do with their anatomy.
锤头鲨从不会停止游泳
The hammerhead shark never stops swimming.
但同一般观念相悖的是 很多鲨鱼会
But contrary to popular belief, many sharksdo.
许多种类 比如柠檬鲨
Most species of sharks, like the lemon shark,
会栖息在水底
can rest on the bottom
并用简单的吞咽动作让水通过鳃部
and move water over their gills by simply gulping.
生物学家称其为“口腔抽吸”
Biologists call it “Buccal Pumping”.
有几种鲨鱼
A few species of sharks,
比如鲸鲨和大白鲨
like the Whale shark and the White shark,
就是强制撞击式呼吸的代表
are known as Obligate Ram Ventilators.
它们只能通过游泳时含氧海水
They can only breathe by ramming oxygenated water
从口部被动进入鳃部来完成呼吸
into their gills through their mouths as they swim.
停止游泳就意味着窒息!
If they stop swimming, they’ll suffocate!
锤头鲨亦是如此
The Great Hammerhead is also an Obligate Ram Ventilator,
所以就得一直游
and has to keep swimming all the time.
别的像大青鲨等鲨鱼也要时刻保持游泳
Sharks such as the Blue shark keep swimming all the time too,
但却是出于完全不同的原因
but for a totally different reason,
因为它们不游就会沉底
because sharks sink if they stop swimming.
鱼类 包括鲨鱼 比海水要重
Fish, including sharks, are heavier than water,
所以会下沉
so they sink.
硬骨鱼类有一个叫做鱼鳔的器官
Bony fish have an organ called a swim bladder
可以调节自身的浮力
that they use to adjust their buoyancy.
通过调节鱼鳔内气体的量
By adjusting how much gas is in its swim bladder,
鱼类就可以保持完美的沉浮状态
fish can keep itself perfectly neutral,
既不会沉 也不会浮
so it doesn’t sink or float.
由于鲨鱼没有鱼鳔
Since sharks have no swim bladder,
它们一旦停止游泳就会沉到水底
they sink to the bottom when they stop swimming.
而像大青鲨一样的一些鲨鱼
But some sharks like the Blue shark
生活在的开阔大洋有数千英尺深
live in the open ocean where the bottom is thousands
海底昏黑冰冷
of feet below where it’s dark and cold.
自然不敢沉底
They can’t rest on the bottom.
为了适应这种环境
So they have adapted to this environment
它们进化出了非常大的胸鳍
by developing very large pectoral fins
并使其像机翼那样工作
to act as airplane wings.
鲨鱼在水中游弋时
As the shark cruises through the water,
胸鳍提供上升力将鲨鱼托起
the fins provide lift to keep the shark aloft,
阻止其坠入冰冷阴暗的海底深渊
and prevent it from sinking into the dark,cold abyss.
胸鳍越大 提供的上升力也就越大
The bigger the pectoral fins, the more lift they provide,
鲨鱼就能在不下沉的状态下游得越慢
and the slower the shark can swim without sinking,
从而节省了能量
which saves energy.
锤头鲨则有着
The Great Hammerhead on the other hand has
不大的胸鳍
small pectoral fins
以及一个叫做cephalofoil的大脑袋
and a big head called a cephalofoil.
该结构似乎能实现多种功能
The cephalofoil seems to accomplish several things
包括更宽阔的视野
for the shark, including expanded vision,
更大表面积的电感受器
a larger surface area for electro-receptors,
以及类似小型翼一样的的额外前端浮力
and additional front end lift like a mini-wing.
但是它也有重量 而科学家们认为此重量
But it also has mass, and scientists think this mass,
与小型胸鳍相结合
combined with small pectoral fins,
正是锤头鲨拥有
is the reason that hammerheads are so much
比其他同体型鲨鱼高得多的机动性的原因
more maneuverable than other similarly-sized sharks.
尽管这对小胸鳍帮助鲨鱼
But while those small pectoral fins help the shark
快速转向以捕捉猎物
turn quickly to catch prey,
它们有一个缺点:不多的上升力
they have a disadvantage: not much lift.
这时就需要倾斜式的泳姿了
And this is where the tilted swimmingcomes in.
安迪·卡萨格兰德的背鳍连续摄影显示
Andy Casagrande’s dorsal fin footage showed
锤头鲨移动时
that when Great Hammerheads are on the move,
它们几乎总是
they are almost always swimming
保持一个大于45度的倾斜角!
at a tilted angle of more than 45 degrees!
2015年 尼古拉斯·佩恩 吉尔·艾欧斯拉夫斯基
In 2015, Nicholas Payne, Gil Iosilevskii
以及其他五名研究员聚到一起调查
and other five researchers got together to investigate
这种奇怪的行为
this strange behavior.
他们将传感器安放到锤头鲨身上
They put sensors on Great Hammerhead sharks
来测量倾侧角
to measure the roll angles.
随后 他们利用风洞测试
Then they used wind tunnel tests
对效果进行建模 以弄清
to model the effect and figured out
鲨鱼到底在干嘛
what the sharks are doing.
鲨鱼将身体侧向一边
The sharks roll on their sides to use
用它们的大背鳍作翅膀
that huge dorsal fin as a wing
借以提供长距离游动所需的上升力
and provide lift while swimming distances.
此举使得鲨鱼获得更多上升力
It allows the shark to generate more lift,
也就可以游得慢一点
which means it can swim a bit slower
而不至下沉 也节省了能量
without sinking, and save energy.
实际上 斜向一边的游泳方式使鲨鱼
In fact, swimming tilted to the side saves the shark
节省了大约8%的游泳耗能
about 8% swimming effort.
因此 鲨鱼需要去往某地时
So when the shark needs to go somewhere,
它就会斜着游来省省力
it tilts to the side and saves energy.
而要捕猎时
But when it needs to hunt,
它就直上直下地游
it swims straight up and down
从而发挥它出色的机动性
to take advantage of the increased maneuverability.
这条大背鳍有两种作用
The giant dorsal fin serves two purposes:
正着身子时用作龙骨
a keel when upright,
斜着身子就成了翅膀!
and a wing when tilted!
这一点上 暂不清楚是否有其他鲨鱼也会如此
At this point, no other shark is known to use this technique,
而潜水员们在锤头鲨身上观察到的
and it explains a mysterious
这谜一样的习惯也就此解开
habit that divers observed in Great Hammerhead sharks.
有时仅是身处海洋就可以获得
Sometimes just being in the ocean creates
对栖息在此的生命的新的了解
new understanding of the life that lives there.
作为潜水员 我们在海洋中的停留太过短暂
As divers, our time in the ocean is fleeting,
每次潜水只有一个小时左右
lasting just an hour or so per dive.
但它却给予了我们一瞥这片蔚蓝中
But it affords us the opportunity to catch a glimpse
无数生命之精彩的宝贵机会
of the lives of the animals that live there.
正是这驱使着我
This is one of the things that keeps me
一次又一次地回到这里
coming back over and over,
哪怕只能短暂一瞥这蔚蓝世界
for my short glimpses into the Blue World.

发表评论

译制信息
视频概述

骨骼惊奇的锤头鲨竟然喜欢斜着身子游泳?!快来看看是为啥吧!

听录译者

收集自网络

翻译译者

伽卡

审核员

审核员 LD

视频来源

https://www.youtube.com/watch?v=zz7NSeSJPOs

相关推荐