Which animal has the best eyesight? - Thomas W. Cronin

翻译人员: 思辰 李 校对人员: Helen Chang

The animal kingdom boasts an incredible diversity of eyes.

在动物的王国里， 存在千百种非同寻常的眼睛。

Some rotate independently, while others have squiggly-shaped pupils.

有些可以控制一只眼睛转动， 有些则有波浪形的瞳孔。

Some have protective lids, others squirt blood.

有些有眼睑保护， 有些会喷血自卫。

But which creature has the best sight?

但其中哪位能一目千里？

Which sees best in the darkness?

谁又能看破黑暗？

Which sees the most detail?

谁洞悉秋毫？

Which animal sees the most color?

谁又能感知到最广的色域？

And finally, which detects motion the fastest?

又是谁，能最敏捷地捕捉到运动？

All eyes take in sensory stimuli in the form of waves of light.

光波在眼睛里造成感官刺激。

To convert these into everything we see,

眼睛再把这些光聚到光感应器上，

eyes focus incoming light onto photoreceptors.

转化成了我们看到的一切。

These cells translate light into neural signals

这些细胞将光转化为神经信号，

and send them to the brain, where they’re finally processed.

并将它们发送给大脑处理。

The eyes that see best in darkness are those that capture

在黑暗中看得最清楚的眼睛，

能够捕捉到尽可能多的光线。

as much available light as possible.

Colossal squids have soccer-ball-sized eyes—

大王酸浆鱿的眼珠 有一个足球场那么大，

the largest known in existence.

是已知的世界之最。

These may help them spot the faint glow of sperm whales

这或许能帮助它们定位到

为了干扰其他发光动物 而产生微光的抹香鲸。

as they disturb light-producing organisms.

Some fish have eyes that are unique among vertebrates because they use mirrors.

有些鱼的眼睛里还有镜子， 这使它们在脊椎动物中独一无二。

For the brownsnout spookfish,

褐嘴幽灵鱼， 用高效聚集光线的微小晶体板

each eye has an upward-facing lens and a downward-pointing mirror

在眼睛里组成了 一上一下的镜子。

composed of tiny crystal plates that efficiently gather light.

They can see up and down simultaneously,

它们可以同时上下观察，

and may perceive distinct shapes, even in the ocean’s depths.

而且就算在深海里， 也能看清远处的形状。

Back on solid ground, arctic reindeer have adaptations

陆地上的北极麋鹿， 可以适应长达数月的黑暗，

to deal with months of darkness.

The backs of reindeer eyes change color, from gold in summer to blue in winter.

它可以改变眼背部的颜色， 夏天变金、冬天转蓝。

Their blue-backed eyes are about 1,000 times more sensitive to light.

蓝色的眼背对光线更敏感 1000 倍。

This may allow reindeer to recognize important things in the snow

使麋鹿能够在雪地中 识别出重要的东西：

like urine and lichen.

例如动物的尿液，以及地衣。

When it comes to the sharpest vision, birds of prey soar above the competition.

一旦谈到最敏锐的视觉， 鸟类可算是名列前茅。

To capture the most detail, an animal must have lots of photoreceptors in its eye,

眼睛里的光感受器越多， 能捕捉的细节就越多。

as well as increased visual processing power.

视觉处理能力也因此提高。

Raptors have an especially deep fovea—

猛禽有非常深的中央凹，

a depression in the back of their eye that fits more photoreceptors.

这个凹陷越深， 能承载的光感受器就越多。

So, Peregrine falcons have vision that’s more than twice as sharp as a human’s.

因此，游隼的视力比人锐利两倍。

They’re able to zero in on a rabbit from more than three kilometers away.

它们能在 3 公里外锁定一只兔子。

When crowning the creature with the best color vision,

什么生物拥有最佳的色觉？

the picture gets complicated.

这问题有点棘手。

Different photoreceptors are sensitive to specific waves of light,

不同的光感受器 对特定的光波敏感。

meaning the colors we see are largely determined

意味着我们看到的颜色

大多取决于 我们有什么类型的光感受器。

by what kinds of photoreceptors we have.

Presumably, the more types of color photoreceptors an animal has,

按理说， 处理不同类型颜色的光感受器越多

the better its color vision.

色觉就越好。

Dogs have just two types.

狗只有 2 种感受器，

Humans have three.

人有 3 种。

And we are far outdone by some birds, fishes, and insects.

在这方面， 鱼鸟昆虫把我们狠狠地甩在身后。

Bluebottle butterflies have at least 15 types of photoreceptors.

蓝凤蝶至少有 15 种光感受器，

Seven of them are attuned to distinct blues and greens,

光是区分蓝绿就有 7 种。

which researchers think might help them track each other during high-speed chases.

研究人员认为，这或许可以 帮它们在高速追逐中互相定位。

Mantis shrimp have a whopping 16 kinds of photoreceptors,

螳螂虾有多达 16 种光感受器，

with five reserved just for the ultraviolet, or UV, spectrum,

其中 5 种用来识别 人眼看不到的紫外线光谱。

which humans can’t see.

But experiments suggest that the mantis shrimp’s ability

不过实验表明， 螳螂虾的辨色能力

to discriminate between colors is more limited than you might expect.

远比你想象的要有限。

Exactly how they use their complex eyes is a mystery.

它们使用复眼的方法依然成谜。

Meanwhile, with just four kinds of color photoreceptors,

金鱼，在另一方面， 虽然只有 4 种光感受器

goldfish actually excel at discerning subtle differences in shades.

却极擅长于辨别 色调中的细微差异。

Finally, insects have mastered the ability to see the world... on the fly.

昆虫们则是飞行中的视觉大师。

The fastest motion vision requires photoreceptors

极速的运动需要光感受器

that quickly sense changes in light,

快速感知光线的变化，

and a brain that rapidly processes the information.

还需要大脑飞速处理这些信息。

A movie shot at 24 frames per second gives us the perception

一个 24 帧速的电影 对我们来说几乎是无缝衔接，

of near seamless motion.

But insects would see a slideshow.

但放给昆虫看，可就是幻灯片了。

Fly photoreceptors register changes 10 times faster than we do,

苍蝇的光感受器 记录变化的速度是我们的 10 倍，

making them especially hard to catch.

这就是为什么它们这么难抓。

These animals have some of the best vision we know of,

这些动物都各自有极佳的视觉，

but there's no winner across the board.

但没有十全十美的赢家。

Each category has different top contenders because vision requires tradeoffs.

因为不同的能力之间相互权衡， 大家都只是在个别类型中取胜。

So, some eyes are highly specialized,

因此，有些眼睛拥有专长，

while others, like ours, perform decently in many categories.

像我们的这些则是多个领域的万金油。

From eyes the size of soccer balls to those that see in UV—

无论是足球一样大的， 还是能看到紫外线的眼睛；

the ways of looking at the world are as varied as the life forms in it.

看待世界的视角 就如生命一般千变万化。