They're tiny animals that grow up to one millimeter long, and have eight legs.

牠們是只有一毫米長，有八隻腳的小動物。

They're also known as water bears.

牠們的另外一個名字是「水熊蟲」。

Their feet look like this, more like claws.

牠們的腳長得很像爪子。

And up close, their faces look like this.

而牠們的臉湊近看長這樣。

Some speculate that there are around 900 known species.

有人推測現今大概有九百多種不同品種的水熊蟲。

They were given the name Tardigrada, by Italian biologist Lazarro Spallanzani.

牠們都被歸類為緩步動物，而這個名字是由義大利生物學家拉札羅．斯帕拉札尼首先提出的。

They're also known as moss piglets.

水熊蟲也被稱為苔蘚小豬。

They typically live around water and damp moss or lichens, but can be found almost everywhere on Earth.

牠們通常住在有水的地方或是潮濕的苔蘚與地衣周圍，但幾乎整個地球上都可以發現牠們的蹤跡。

Some theorize they might have come from space, of course, this is just a theory.

有些人推論水熊蟲可能來自外太空當然，但這當然也只是猜測而已。

They can survive dry periods by curling into little balls.

在極為乾燥的環境下，水熊蟲可以藉由蜷曲成球狀繼續生存下去。

They can hang around like that for 100 years, before casually regenerating.

他們可以維持這個型態持續一百多年，然後若無其事地再次重生。

Some species are carnivorous.

有些水熊蟲為食肉動物。

Some might even eat other Tardigrades.

有些甚至會吃自己的同類。

So, how resilient are these little guys?

所以，這些小傢伙的生命力到底有多強呢？

They can withstand 1,000 times the lethal human dose of X-ray radiation.

他們可以承受的致命 X 光輻射量是人類的一千倍。

In 2007, some Tardigrades hitched a ride on a space shuttle and lived outside the spacecraft in an oxygen-deprived vacuum of space for 10 days.

2007 年時，一些水熊蟲上了艘太空梭，並在太空梭外的真空狀態下生活了十天。

Many survived.

而不少水熊蟲撐過去。

All of which means, it's probably impossible to kill a tardigrade.

這也代表著，要殺死水熊蟲大概是不可能的事。