Tardigrades, or water bears, are tiny aquatic invertebrates that can survive extreme conditions. Since their discovery, they have mesmerized scientists and all those with a curiosity about nature. These amazing animals, all less than a millimetre long, have adapted to live in almost every habitat on earth for hundreds of millions of years. They have survived in that same, unchanged, form since the Cambrian period. That would be a real miracle and a testament to the amazing resilience of life over deep time.
Scientists at universities like the University of Plymouth have spent a lot of time learning about these incredible organisms. Tardigrades are the only organism to have survived all five mass extinctions, evidence of their uniqueness and adaptability. They have an incredible knack for survival through adversity. These astonishing creatures are capable of withstanding temperatures that drop near absolute zero up to a blistering 130 degrees Celsius. They can be exposed to radiation doses fatal to humans, but come through radiation-cocktail fashion.
The unusual appearance of tardigrades only adds to their intrigue. Some look like an inflatable version of the Michelin man, others have plates or scutes of armor like that of an armadillo or pillbug. Their eight chubby legs are tipped with claws, like tiny bear paws on each leg, making them even cuter.
Tardigrades live in moss, where they flourish out of sight of the naked eye. To find them, one can rinse moss with water and examine the remaining material in a microscope. This deceptively simple technique unlocks a hidden universe of diverse and beautiful microscopic wonders that has captivated early microscopists just like us since the 1600’s.
Take for instance a recent study that praised marine tardigrades for their hardiness against climate change. In worst-case climate scenarios—with increases of 5-degree Celsius predicted by 2100— researchers found that the rugged tardigrades were still undeterred. This peculiar and pronounced resilience to severe environmental transformations makes them ideal, and obvious, candidates for bioindicators of ecological wellbeing.
As small as they may be, tardigrades make a cute animal ambassador for life’s ability to persist against the odds. Their majestic range across the terrestrial planet is a profound scientific question. It even encourages us to explore nature’s remarkable power to endure.