Tardigrades – The Immortals Among Us

Muhammad Ahsan, Reporter

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We all have a few favorites when we think about picking the toughest animal on Earth. Some of these favorites include Gorillas, Lions, Elephants and Bulldogs (because why not?). The truth is that the toughest animal is actually none of those. It is a bear and not the types of bear you are probably thinking about. The name is Tardigrade also known as the water bear.

Tardigrades are extremophiles. An extremophile is an organism that thrives in physically or geochemically extreme conditions that are detrimental to most life on Earth. Tardigrades can survive 1000 times the radiation that would kill an elephant, can withstand pressures of 87,000 lbs per square inch which is up to 6 times in the deepest oceans of Earth, can survive without food or water for decades and stay alive in temperatures as low as 1 K and as high as 420 K. Not only that, scientist have been sending these adorable creatures in space for a while now, and they always return alive and healthy proving that they can survive in the most inhospitable environment known to us, Space.

A human can barely survive for about 100 hours without water, but these cute creatures can survive without it for decades. They do this through a  process called Anhydrobiosis which is a type of cryptobiosis. Cryptobiosis is a physiological state in which metabolic activity is reduced to an undetectable level without disappearing altogether preventing reproduction, development, and repair. During anhydrobiosis the animal enters an almost entirely desiccated state which stabilizes its membranes and other cellular structures through a matrix, preventing otherwise lethal damage caused by environmental extremes. In other words, they temporarily die and wait for the conditions to become favorable again.   

There are about 1100 known species of tardigrades, and they are found just about everywhere including Antarctica (and your backyard). Scientists are studying tardigrades to figure out how they manage to survive all these extreme stresses especially cell death caused by the expansion of water at extreme temperatures. The most intriguing question is why evolution equipped them with such extreme survival skills with no apparent use (don’t you think that they are a little overqualified for just sucking on moss)?

They have survived five mass extinctions over the course of around half a billion years. Cockroaches surviving nuclear wars is old news now (we weren’t that excited about that anyway), these adorable bears will probably survive until our sun dies (like literally). They are as close as it gets to being immortal on Earth.

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