if you're immersed in water for longer than 10 minutes, chances are your fingers and toes

如果你浸在水裡超過10分鐘，很有可能你的手指跟腳趾

will emerge looking like raisins. So what's up with the wrinkle digits?

將會出現像葡萄乾一樣的皺痕。這皺皺的指頭是發生什麼事了？

For years, a scientist study the phenomenon was the result of some type of osmosis

多年來，科學家研判這樣的現象是出自某種滲透性的結果，

caused by water passing into the dry outer layer of skin.

由水流經皮膚乾燥表層造成

The influx of water, the thinking wet would expand the skin surface area but

水的匯集會擴展至皮膚表面區域而

not the tissue below its. The skin would bunch up and wrinkled. But in 1935

不是底下的組織。皮膚會聚成一團，變得皺皺的。但在1935年，

a pair of doctors noticed that this affects didn't happen

兩位醫生注意到這樣的現象並未出現在

in their patients with nerve damage. One patient, for example, was a boy who had lost feeling in three of his fingers

有神經損害的病患們身上。舉例來說，病患其一是個有三根手指失去知覺的男孩

The researchers found that when his hands got wet, the fingers that could feel

學者們發現當他的手弄濕後，正常的手指

wrinkled as normal, but the ones that were numb, remain smooth.

會有皺痕，但麻木的那些手指，仍維持平滑狀態

It turned out that the pretty digits weren't caused by just a passive flow of water through the skin,

結果顯現指頭並不是單單因為水在皮膚被動地流通而造成，

it was an active responsive of the nervous system to prolonged moisture.

它是神經系統主動地反應，以延續水份

The nervous system causes the wrinkling by constricting the blood vessel below the skin

神經系統藉由壓縮皮膚下的血管造成皺痕

which causes the upper layers of skin to pucker.

這造成皮膚上層有皺摺

Since the phenomenon is caused by an involuntary nervous bound,

既然這個現象是非自主性的神經躍動造成

some biologists have thought that it must have some evolutionary function.

部分生物學家認為它可能有某種進化性功能

But what possible purpose could it serve? One recent theory

但它可能用於哪種目的呢？一個近期的理論

suggests that wrinkly skin may have given our ancestors a better grip on

顯示皺皺的皮膚可能讓我們的祖先受益於

working in wet conditions, like gathering food from a stream, or damp vegetation

在潮濕的環境工作，像是從小河裡採集食物，或者潮濕的植物。

May have also given us better footing while walking across the landscapes in the rain.

也可能讓我們在雨中能更好的立足、行走

In a 2013 study,

在一項2013年的研究，

evolutionary biologists tested this theory by asking subjects with either

生物演化學家驗證此理論，憑著詢問手指有皺痕的受試者

wrinkly or non wrinkly fingers to pick up a variety of wet and dry objects like marbles.

及手指上沒皺痕的人去撿起不同種類的潮濕、或者乾燥的物體，大理石就是其中一樣

They found that the subjects with wrinkly digits picked up the wet objects 12 percent faster

他們發現手指有皺痕的人撿起潮濕物的速度是

than their counterparts, but there was no difference when it came to picking up dry objects.

對照組的12%快，但如果是撿起乾操物，便沒什麼差異

The wrinkles apparently helped channel the water away

顯然地，皺痕能夠把水引開

much like the treads on your car's tires. So then this raises the question,

就像汽車輪胎胎面上的紋路。這就引起了一個問題，

if wrinkly skin gives us a better grip, then why isn't our skin wrinkly all the time?

如果皺皺的皮膚帶來助益，我們何不一直保持這樣的皺紋？

Well, maybe because shriveled fingers and toes are less sensitive,

這個嘛，很可能是因為乾燥的手指腳趾比較不敏感吧

which is no advantage at all. Thanks for asking, and if you'd like to submit questions

這也不是什麼很大的優點啦。感謝提問，如果你想要問問題，

for us to answer, or get these quick questions a few days early

或者想提早幾天看到這些問題

check out PATREON.COM/SCISHOW, don't forget to go to YOUTUBE.COM//SCISHOW and subscribe.

看看 PATREON.COM的SCISHOW，別忘了上YOUTUBE.COM的SCISHOW頻道訂閱