The Last Animal Life on Earth will be… Microscopic Bears

Tardigrades aren’t really bears, of course, but they do resemble little eyeless bears with a few extra legs. It turns out they are pretty amazing, and much better than humans at survival. They are so much better, in fact, that they may be the last animal life on Earth some day.

In the face of numerous threats to humanity, including climate change, nuclear war, and disease, one tiny creature stands out as the ultimate survivor: the tardigrade. These microscopic organisms, also known as water bears or moss piglets, are remarkably resilient, capable of withstanding extreme conditions that would be fatal to most other living beings. Tardigrades, typically measuring around 0.5 millimeters in length, can survive temperatures ranging from as low as -450°F to as high as 302°F. They can even endure decades of exposure to -4°F temperatures, a feat that would prove fatal for humans in a matter of hours.

Tardigrades: The Indestructible Survivors of the Earth

Tardigrades, also known as water bears, are the most resilient species on our planet. These microscopic creatures have the remarkable ability to survive in extreme conditions, including the vacuum of space, intense radiation, and even the impending doom of our sun’s explosion, which is predicted to occur about a billion years from now.

The primary reason for their durability is their ability to enter a state of cryptobiosis, which is remarkably close to death. In this state, their metabolic activity is reduced to undetectable levels, and their bodies contract, losing all but 3 percent of their water, effectively becoming completely dehydrated.

Scientists are still researching cryptobiosis, which some have called a “third state between life and death,” as well as other aspects of tardigrades’ biology. When researchers sequenced the creatures’ genome in 2015, they found that nearly a sixth of tardigrades’ DNA came from foreign organisms, compared to just 1% for most animals. This phenomenon occurs because tardigrades’ DNA breaks into small pieces when under intense stress, such as extreme dryness. When the cells start to rehydrate, their membranes and the nucleus housing the DNA temporarily become leaky, allowing other large molecules to pass through. They repair their own DNA and absorb foreign DNA when rehydrating, resulting in a patchwork of genes from other species.

In 2016, scientists from the University of Tokyo also discovered a new protein in tardigrades that shields them from harmful radiation. These abilities have challenged how scientists understand the process of evolution and have yielded clues about ways we could increase human survival.

The researchers conclude that if the emergence of life on other Earth-like planets gives rise to organisms as durable as tardigrades, the chances are good that life is still around on those planets, even if their sun has exploded.

 

 

… tardigrades are small invertebrate animals, 0.004 to 0.04 inches (0.1 to 1.0 mm) in body length, that live in terrestrial mosses, soil, or lichens. They also inhabit ocean and polar regions.”  … Recent research has shown that water bears can survive the dangerous conditions of space. Previously, the only organisms that have been exposed to the radiation and vacuum of space and lived to tell the tale are certain types of bacteria and lichen. That simple animals like tardigrades also can survive gives more credence to the theory of panspermia, which claims that organisms could move from world to world after travelling though space. Knowing the survival tricks of water bears also could one day be a key component in enabling the human exploration of the universe. [1]

Would they survive on Mars?

While they could survive in their dried out form on mars, water bears wouldn’t evolve or do anything interesting there because there is no water. They’d just stay dormant.  Another fact from the article that may surprise you is that the sun will make the earth uninhabitable in only a billion years.

In a few billion years, the sun will become a red giant so large that it will engulf our planet. But the Earth will become uninhabitable much sooner than that. After about a billion years the sun will become hot enough to boil our oceans. [2]

We could go extinct much sooner if we get hit with a massive space rock.

My hope is that humanity gets organized soon, stops fighting about stupid things and works together to improve our collective odds of survival. Using our collective intelligence is our best chance to beat moss pigs / water bears in the animal life survival game.

Citations

[1] https://www.space.com/5974-alien-water-bears-amaze-scientists.html
[2] https://m.phys.org/news/2015-02-sun-wont-die-billion-years.html