Seth Messenger : The infinite robustness of tardigrade

Tardigrade measures no more than two millimetres. Yet it is one of the most robust beings known on the planet.

A head, a nervous system representing 20% of the cells, a body protected by a cuticle and eight legs that end with claws. Nothing else to shelter the tiny animal that knows how to live anywhere, in all climates, with, as a favorite place, the wet moss of stones and roofs.

But this global habituation is nothing compared to the incredible resistance of the animal which is able to withstand the most extreme conditions. So extreme that they are not found on Earth and that some scientists do not hesitate to evoke an extraterrestrial origin to this animal discreetly present all over the planet.

It is resistant to absolute vacuum, with temperatures of -253C to 151C. Can withstand pressures greater than three hundred times atmospheric pressure, ingest or breathe chemicals or toxics, subject its shell to radiation eleven hundred times greater than the lethal doses for a human. And when he is in imminent danger of death, the tardigrade at the ultimate parade: He enters cryptobiosis.

Cryptobiosis is a third state, between life and death.

A state in which vital activity becomes virtually undetectable to 0.01% of normal. The passage into this state involves dehydration, replacing the large volume of water contained in the body with a substance that tardigrade synthesizes. Said substance preserving the integrity of all cellular structures, including neurons. In other words, tardigrade has the ability to put his life on hold. And this for several hundred years!

As soon as conditions return, tardigrade rehydrates by feeding on water. It then takes only a few hours, or even a few minutes, to resume the normal course of its existence. As if the centuries had passed had been a simple night's sleep.