Buzz
Incredibly small yet undeniably impressive, tardigrades perfectly embody the saying that big things can come in tiny packages. And with their irresistibly cute nicknames, how could anyone resist? Water bear or moss piglet—could they get any more adorable? And yes, not everyone might agree on their cuteness, but those tiny legs and squishy bodies? Hard to deny the charm!
Even if they don’t win any beauty contests, the remarkable facts about tardigrades are enough to spark anyone’s curiosity. These incredibly resilient creatures thrive in almost any environment with water. Since Earth is mostly covered by water, you’ll likely find them just about everywhere. Let’s take a closer look at what makes these miniature animals so mind-blowing.
10. What Exactly Are They?
There are over 1,100 species of these fascinating micro-animals. Tardigrades are often linked to arthropods like crustaceans, spiders, and other insects, but their exact classification remains elusive. Their resemblance to certain arthropods is the reason they might be classified this way, but their many distinct characteristics make it difficult to place them firmly in the arthropod family. It’s entirely possible they represent a whole new branch of life! Once thought to be more closely related to bacteria due to contaminated samples, further research debunked this misconception.
In essence, tardigrades are multi-cellular organisms that evolved from eukaryotic cells, meaning their genetic material is housed in a central nucleus. To keep it simple, this means they are made up of more cells than bacteria, which are single-celled organisms. It’s easy to spot this difference now that we can see them up close—thank you, modern technology!
9. Small Body, Big Bite
Photo credit: Wikimedia Commons
Tardigrades fall under a unique group of animals called extremophiles, meaning they can survive in environments where most other creatures—including humans—would not stand a chance. Their translucent bodies feature an exoskeleton with four segments and eight short, stubby legs, each tipped with four tiny claws used to grip the surfaces they feed on. Their heads form a distinct fifth segment, though they might appear a bit flattened. Tardigrades typically measure between 0.5 and 1.2 millimeters (0.02 to 0.05 inches), but rarely grow larger than 1 millimeter. And, yes, their mouths are a little on the creepy side.
The tardigrade's mouth is round and can extend outward like a spear. It’s filled with sharp, needle-like teeth called stylets, which they use to puncture and then suck out the liquid from their meals. We’ll talk about what they eat a bit later, but don’t worry—they aren’t like mosquitoes or spiders that feed on blood. Thankfully, humans aren’t on their menu either. At least, not yet.
8. Surviving Through the Ages
Photo credit: Wikimedia Commons
Though tardigrades have only recently received extensive study, they were first discovered back in 1773 by German pastor J.A.E. Goeze. Three years later, Italian biologist Lazarro Spallanzani named them Tardigrada, meaning ‘slow stepper.’ Recent research has shown that their history stretches back far longer than when humans first took notice of them.
Realistically, tardigrades are likely among the oldest terrestrial life forms. They've been around for an astonishing five hundred million years or more. So much for humans being the most well-adapted survivors! Look at bacteria and other microscopic life forms that have existed long before humans and still thrive today. It’s a pretty incredible and magical world if you take the time to step outside the usual human mindset. Put your smartphone down and start exploring… but only after you finish reading this, of course!
7. Desiccated and Frozen…Yet Still Alive
Tardigrades are typically found in water, especially fresh water, but they actually live in any environment on Earth where water can be found. From Antarctica to tropical rainforests, mountaintops, oceans, and even sand and soil—these creatures are everywhere! One of the easiest places to find them is in the thin layer of water that coats mosses and lichens. So, yes, you could even find them in your own backyard, particularly if you're near a freshwater source!
While tardigrades are aquatic, meaning they need water to survive, they require it to help with gas exchange and to prevent desiccation—think of it like being a sun-dried tomato or dehydrated fruit. However, if removed from water, they don’t die. They can actually be revived when returned to water! And that’s not all—these creatures can even endure freezing temperatures for long periods and be brought back to life once thawed. How cool is that? With each new discovery, they’re becoming even more amazing!
6. A Fungi-Focused Diet
So, what do tardigrades munch on? They primarily feast on mosses, flowering plants, bacteria, and lichens, also known as fungi. They’re also known to suck up animal cells, and yes, some of them are cannibalistic, even eating other tardigrades! Using their unsettling mouths, they pierce the cell walls and membranes of their prey to suck out the nutrient-packed fluids. Thankfully, they don’t crave human flesh, or their cuteness would definitely be compromised.
Now, imagine this from a scientist’s perspective: just think about how many ways tardigrades may have helped by consuming bacteria that could’ve led to more plagues or diseases. These little, plump miracles are swimming all around us. Miniature, water-dwelling angels!
5. Survival Like No Other
Let’s dive a little deeper into their astonishing ability to revive themselves, which has captured the interest of scientists. Through a process called cryptobiosis, tardigrades can slow down their metabolism to a minuscule 0.01 percent, effectively allowing them to survive without food. Their organs are shielded by a sugary gel that continues to generate high levels of antioxidants.
When exposed to extreme cold or dehydration, tardigrades form a protective state known as a tun. They curl up into a tiny ball by pulling in their head and hind legs. In freezing temperatures, they even manage to prevent ice crystals from forming inside them. Science still has a lot to learn about this incredible survival skill.
If the water they inhabit has lower-than-usual oxygen levels, tardigrades can stretch out, slow down their metabolism, and absorb oxygen through their muscles. As if that wasn’t already mind-blowing enough, they can also produce a protein that shields their DNA from radiation damage. They’re also resilient to harmful chemicals, low-pressure vacuums, boiling alcohol, high pressure like the depths of the ocean, and shifts in water salinity. It’s no surprise they’ve survived so many mass extinctions over time!
4. Get Ready for Impact
Despite their remarkable survival skills, water bears aren’t invincible or immortal. It may seem that way, but they do have weaknesses and will eventually meet their end. For instance, they absolutely cannot survive human stomach acid—good thing, because you've probably ingested some without even realizing it. Their natural lifespan is about two and a half years, as long as they aren’t frozen or dried out. And they can’t withstand an impact exceeding 3,218 kph (2,000 mph). Yes, humans have actually shot them out of guns to test how far their survival abilities go. Humans can be so strange.
Recently, scientists discovered that tardigrades’ lifespans are significantly shortened when exposed to water temperatures of 38°C (100°F) or higher. Climate change might be just as dangerous to them as it is to all other life forms. We really need to take control of our habits that are accelerating this process for the sake of all life. Let’s start a campaign to save the bacteria-fighting, water-dwelling moss piglet!
3. Tiny Alien?
Due to their incredible and almost otherworldly traits, there’s a growing theory that tardigrades might actually be aliens who arrived on Earth via a meteor. While this is more fiction than fact, it hasn’t stopped people from calling them extraterrestrials. After all, we did accidentally send them to the moon. Poor little water angels.
An Israeli spacecraft was transporting thousands of tardigrades to study how they would fare in space’s vacuum and various radiation types. Unfortunately, the craft crashed and ended up on the moon. The water bears were in a hibernation-like state and encased in artificial amber. The program’s director firmly believes that these moss piglets likely survived and remain in their suspended animation. So, in a way, the tardigrades are now astronauts too. It’s truly fascinating.
2. Males Not Required
The Moss Piglets have some rather unique reproductive methods. Certain species reproduce asexually, where the female lays the eggs, and they develop independently, without the need for fertilization. Efficient, yes, but perhaps a little lacking in the fun department. This process also means that males are unnecessary (wait, what?). If you’re a fan of science fiction or horror films, check out No Men Beyond This Point to see what could happen if humans followed the self-reproducing ways of the tardigrade!
For species that do mate, the female lays anywhere between one and thirty eggs, which are embedded in her molting cuticle. Once the male arrives, he wraps around her, and together, they engage in stimulation, which sometimes lasts an hour or more. The male then releases sperm beneath her skin. In other species, the female sheds her cuticle entirely and lays the eggs within it, waiting for the male to fertilize them later. The eggs take about 40 days to develop, or 90 days if they’ve been dehydrated. Not exactly the most romantic of processes.
1. Walk This Way
Watch them move! There are now videos out there, and they’re absolutely adorable. When not swimming, tardigrades shuffle along with their eight tiny legs, looking for moss and mushrooms to feast on. Their walking style is quite like insects that are hundreds of thousands of times their size, or even like crustaceans. It has a surprising resemblance to galloping, albeit much slower. Ever feel like you’re moving like a tardigrade before your morning coffee?
As aquatic creatures, tardigrades live up to their nickname—water angels (let’s get this trending!). Of course, they can swim too. They use those same tiny legs to glide through the water, and they’re surprisingly faster swimmers than walkers. They also float, but it’s usually on bits of debris rather than just floating freely. So, their floating looks more like surfing. They’d probably totally crush the competition at Pipeline in Oahu, Hawaii.
