For a creature to be labeled as the toughest one in the world, what capabilities does it have to possess?
Does it have to be able to withstand extreme temperatures of 300 degree Celsius or minus 200 degree Celsius?
Does it have to be omnipresent and live in all places on Earth starting from hot springs to the Himalayas, deep sea to mud volcanoes, mosses to rain forests, freshwater to the Antarctica?
Or do you fancy it being able to live for more than 30 years without water or food? Does it have to survive in outer space or without air?
Does it have to live through a complete global mass extinction event such as a meteorite landing or gamma-ray explosion?
If yes, scientists have already discovered the toughest creature in the world. Tardigrades are near-microscopic creatures that can survive all these extreme situations and are estimated to outlive not just humanity, but also the Earth.
The species of Tardigrades, also known as little water bears or moss piglets, are barrel shaped, eight legged animals that have the anatomy to survive in the most extreme environments that are unimaginable for any other species to live through.
The name “little water bear” was given to the animal due to its bear-like gait in 1773. The creature was renamed as “Tardigrade” in 1776, rooted in the word tardigradum, meaning a slow walker. They range from 0.3-0.5 mm in length and hence, the name “little” water bear.
In such situations, a tardigrade transforms into the cryptobiotic state, where metabolism is suspended and water level drops within the organism. In this state, a tardigrade is called a tun and scientists claim to have studied tuns that were about 120 years old.
Although they can survive various extreme situations, they cannot adapt to the conditions. They are extremophilic, which means that the longer a tardigrade is exposed to such conditions, the chances of dying increase for the creature.
Read on to learn about some extreme conditions that a tardigrade can survive in.
A tardigrade can survive extreme temperatures for varying periods of time. While the creature can survive in extreme temperatures such a 151 or -272 degree Celsius, it can survive a few days at -200 degree Celsius and more than 30 years in -20 degree Celsius. Tardigrades are the only species of animals to survive five mass extinctions.
Tardigrade are animals that can survive the pressure six times the water pressure in the deepest trench on Earth, the Marina Trench. It can live through the pressure of open space vacuum and solar radiation combined for at least 10 days.
A tardigrade can survive without water in a dry state for almost 10 years and in freezing temperatures, uses dehydration to keep the animal from being ripped apart by ice due to high water content in the body.
Tardigrades can survive up to a thousand times more radiation than any other species in the world. They can withstand 5000 Gy (a unit of measurement) of gamma rays and 6,200 Gy of heavy ions (5-10 Gy is fatal to a human). The low density of water does not allow ions to react and their high DNA repair capacity makes survival through atomic blasts like Hiroshima-Nagasaki’s possible.
The first known animals to survive outer space are tardigrades. In 2007, a group of dehydrated tardigrades, or tuns, were taken to outer space. They survived the vacuum of outer space and the solar radiation for ten days. When they were re-hydrated back on Earth, 68% of the animals went back to normal within 30 minutes of hydration.
The unique ability of tardigrades to survive in such extreme environments has labeled them as a very important species of animals for space study. By being present in extreme conditioned places, tardigrades attract populations of predators by being their food and help to create more ecosystems in rare places on earth.