科学美国人60秒 SSS 生物发光帮助猎物避开饥饿海豹（在线收听）

This is Scientific American's 60-second Science. I'm Jason Goldman.

这里是科学美国人——60秒科学。我是杰森·古德曼。

Deep in the inky depths of what's called the ocean's mesopelagic zone, more than 500 meters below the surface,

在海面以下500多米被称为海洋中层带的漆黑深处，

the main source of light is not the sun—even during the day.

主要光源也不是阳光，即使在白天也是如此。

Most of the light comes instead from bioluminescent organisms, creatures that produce their own light.

大多数光线来自生物发光的有机体，即自已产生光的生物。

It's in these dark depths that southern elephant seals love to feast on squids and fish.

正是在这些黑暗的深处，南象海豹开心地享用乌贼和鱼。

"Initially we wanted to know how elephant seals find their prey in the dark."

“最初我们想知道南象海豹如何在黑暗中找到猎物。”

Pauline Goulet from the University of St. Andrews Sea Mammal Research Unit.

圣安德鲁斯大学海洋哺乳动物研究部的波琳·古莱特说到。

Thanks to data-logging technology, researchers have a fairly good handle on how far elephant seals travel to feed—and how long and how deep they dive.

得益于数据记录技术，研究人员对南象海豹的觅食距离、下潜距离和深度有了相当好的了解。

But nobody really knew how they find their prey in the darkness. Do they track the lights? Or is something else going on?

但没有人知道他们如何在黑暗中找到猎物。它们是追踪光线吗？还是有别的方法？

"So we built a sensor that could pick up flashes produced by animals that were being hunted by the elephant seal,

“我们制造了一个传感器，可以接收到被南象海豹捕获的动物发出的闪光，

because we thought that elephant seals might be looking for that light to catch a snack."

因为我们当时认为南象海豹可能通过追寻光来捕食。”

But it turned out that the fish actually used their bioluminescence to disorient seals after the seals began their attack.

但结果发现，鱼类实际上是在海豹开始攻击后，利用自已的生物发光来让海豹迷失方向。

"The thing is it seemed that the flashing prey were harder to catch than the nonflashing prey—

“关键是闪光的猎物似乎比不闪光的猎物更难捕捉，

which we found out by looking at the duration of the chase, which was longer for flashing prey."

我们通过观察追捕的持续时间发现，追捕闪光猎物要花更长时间。”

The fish flash was always emitted just after the seal launched an attack, making it a defensive, reactive maneuver to distract the seals.

鱼总是在南象海豹开始攻击后再发出闪光，使其成为一种防御性的、反应性的策略，以分散海豹的注意力。

But at least one seal learned to turn that liability into a hunting strategy.

但至少有一只海豹学会了将这种不利因素转化为捕猎策略。

"This seal appeared to be a master in catching the flashing prey,

“这只海豹似乎是捕猎闪光猎物的高手，

because each time it tried to catch a prey, first it would do this little head movement that was probably mechanically sensed by the prey.

因为每次它试图捕获猎物时，它会先稍微动下头部，这很可能被猎物机械性地感觉到。

Then it would induce the prey to flash, because the prey reacts to this approaching predator."

之后它会诱导猎物闪光，因为猎物会对靠近的捕食者做出反应。”

This seal would twitch her head, see where the light came from and only then start the chase.

这只海豹会晃动头部，看看光来自哪里，然后才开始追捕。

So even if some seals can use bioluminescence as a way to find food, for most the light is a distraction.

因此，即使有些海豹可以利用生物发光来寻找食物，但对大多数海豹来说，光会分散它们的注意力。

Goulet thinks that seals probably rely more on their whiskers to sense the movements their prey make in the water.

古莱特认为海豹可能更依赖它们的胡须来感知猎物在水中的动作。

"It's just a step forward into understanding what's happening in these depths, in this ecosystem that we don't really know much about—especially in the Southern Ocean."

“这只是进一步了解在这些海底深处、这种生态系统中发生的情况，我们对二者都不太了解，尤其是南大洋的情况。”

Thanks for listening for Scientific American's 60-second Science. I'm Jason Goldman.

谢谢大家收听科学美国人——60秒科学。我是杰森·古德曼。