These amazing animals are able to withstand lethal doses of radiation.

If someone mentions "water bears" in a conversation, they're likely to encounter surprised expressions from their interlocutors, who are probably imagining some kind of gigantic amphibious mammal they didn't learn about in class. If, instead of the nom de guerre, they use the official one, the result may not be very different, because not many people are familiar with the existence of tardigrades, one of the truly amazing animals that inhabit the Earth, capable of surviving the most extreme conditions on the planet... and in outer space! A recent article published in the journal Science reveals the possible secret of this unusual resistance.

The truth is that tardigrades don't look much like bones, although the comparison was made by those who first observed them in the 18th century. For starters, they don't have a single hair. But the most important difference is their size: they measure just over half a millimeter long. Seen under a microscope, they look like eight-legged, very slow-moving sausage worms (hence their name, which in Latin means "those who walk little by little"), giving them the appearance of an endearing cartoon character made of cotton. Nothing could be further from the truth: tardigrades are possibly the most resilient animals we know.

In a state of suspension

Since their discovery, they've been studied for their incredible ability to withstand anything you throw at them thanks to their ability to enter a state of "suspension," called cryptobiosis, from which they recover when conditions are once again suitable. This way, they can survive temperatures close to absolute zero or, at the other extreme, almost 150°C, as well as a lack of oxygen and high pressures. As if this weren't enough, they're also capable of going without water or food for years, only to continue living and reproducing peacefully once rehydrated. Tardigrades have even been taken into space, where they survived for ten days in extreme conditions of cold, vacuum, and radiation. Since the first experiment of this kind in 2007 (although the idea of taking them for a ride in a rocket dates back to the 1960s), tardigrades have even become residents of the International Space Station.

There are up to 1,500 known species, although only a few have been thoroughly examined. A new one is found in this group, the Hypsibius henanensis, isolated from a moss found in the Funiu Mountains in Henan Province, China. It was discovered by chance by a group of Chinese scientists, led by Lingqiang Zhang of the Beijing Institute of Lifeomics, who performed an in-depth genetic analysis before and after exposing it to high doses of radiation. The first thing they noticed was that of the more than 14,000 genes in its genome, 30% are exclusive to tardigrades, meaning they have not been seen in any other animal. They may be responsible for the unique characteristics of these organisms. They also discovered that, after being irradiated, tardigrades activate a high number (around 3,000) of genes that protect DNA and repair it if necessary.

Prevent cancer

DNA damage caused by radiation (or other stresses) can not only produce mutations (responsible, for example, for cancer), but also the death of cells or even the entire organism. These tardigrades can withstand up to a thousand times a dose that would be fatal to humans, and this is likely due to the complex protective system they have developed. Scientists believe that some of these genes have been "stolen" from other species throughout their evolution. For example, among the protective genes are some that produce betalains, antioxidant pigments unique to bacteria.

Tardigrades are fascinating creatures that, beyond the biological curiosity they represent, can teach us many things about how to overcome the stresses that surround us. Optimal for our fragile bodies. Without having to go that far, the ability to repair the damage caused by radiation and other toxic stimuli could be an effective way to prevent cancer.

dinosaurs, just as they share it with us now, and with whoever comes after us if we ever disappear. It doesn't seem like they have to worry about the issue of extinction.