The Possibilities of Tardigrades
Meet the tardigrades, also know as “moss piglets” and “water bears”. These microscopic animals look like tiny bears and are no bigger than a grain of sand. They usually have a short natural lifespan of a year and live in damp moss and lichen environments extremely vulnerable to drought. They can easily be killed by being squished. And yet, they take the title of one of Earth’s most indestructible animals.
Tardigrades are extremophiles- they can live in conditions that would kill most animals. For example, they have endured being dipped in pure alcohol as well as exposure to poisonous gases. The little animals can survive for decades without food or water. They have also lived in both temperatures above boiling and temperatures close to absolute zero.
Tardigrades have even been to space. In these conditions, they survived through weightlessness, extreme cold, having no air, and considerable amounts of radiation. Even after being fully exposed to high amounts of solar radiation after the UV filters on the tardigrades’ containers were removed, some of the tardigrades still survived.
As a result of their near indestructibleness, they have survived several of Earth’s mass extinctions. Tardigrades may also have colonized the moon. Back in the summer of 2019, an Israeli moon probe with tardigrades on board crashed on the surface of our most famous satellite. It’s probable the intrepid little creatures are still alive up there.
However, they do have some limits. When exposed to very high temperatures or very large amounts of radiation, most tardigrades die. And as mentioned before, tardigrades can just be squished. Ultimately though, they are much more resistant to conditions that easily kill most lifeforms, so they are still very impressive and could drive important scientific discoveries.
The tardigrades’ resistance has mainly been attributed to their ability to become dormant for decades at a time. The skill likely evolved so that the tardigrades could survive sudden drought, as in their natural state they need a lot of water in their immediate area to live and are very vulnerable.
This is called the anhydrobiosis or “tun” state, where tardigrades retreat into a dry, seed-like state. Tardigrades are able to slow their metabolism to 0.01 percent of normal, essentially pausing their cells until they can be hydrated. Anhydrobiosis is reliant on a set of proteins unique to tardigrades that is believed to help with protecting cells. It’s not entirely clear how anhydrobiosis works, but it may be that the proteins form a kind of biological “glass” inside the tardigrade body that pauses cells.
Anhydrobiosis may have practical applications if humans can figure out how to scale it up as medical technology. Its pausing ability could theoretically be used to save vital time after potentially lethal injuries, both in combat and civilian life. A lot of severe injuries get much more dangerous and harder to treat in a short amount of time, so the ability to pause the natural processes of cells — including cell death and bleeding — could help in these cases.
Furthermore, this ability could help preserve certain kinds of drugs, in-vitro eggs, and organs without needing refrigeration. It could also theoretically be used to pause whole human bodies in emergencies or for the purpose of space travel, a concept which sounds very far-fetched (and probably is).
Plus, some of the other proteins tardigrades have at their disposal have been shown to protect cells from radiation, even when applied to small amounts of human cells, which could potentially help make radiotherapy safer. Right now, though, research is at a very early stage.
If you’re worried by the prospect of evading death by unnatural means, you probably don’t have to be afraid. Even if tardigrade skills are somehow able to be scaled up as treatments for humans, they would only pause cells in emergencies and improve radiation protection. It’s not like it’s the cure to aging. Perhaps the more immediate ethical question is what happens if research isn’t fruitful, since that would mean people have been trying to massacre tiny bears for no reason.
Information Sources
https://www.nationalgeographic.com/animals/invertebrates/t/tardigrades-water-bears/
https://www.britannica.com/animal/tardigrade
Picture Sources
