Our Better Nature: Let’s Make Tardigrades the Hot New Mini-Pet

The tiniest and most endearing animal you’ll ever meet is plump, colorful, and even paper-trained.


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Given the host of proven health benefits of pet ownership, it’s no surprise that about seventy percent of U.S. households now include a pet. In the eyes of many folks, small animals are cuter, and they’re certainly more practical for urban apartment-dwellers. Especially among the Gen-Z and Millennial cohorts, the trend in recent years is toward all manner of petite pets.

While guinea pigs and hamsters are little critters by nature, “pocket-size” puppies and piglets are bred to be that way, frequently with tragic results. So-called “teacup dogs” suffer from issues like fragile bones and organ failure, leading to warnings from Humane Society International and other animal-welfare agencies to avoid them. And in spite of sales pitches to the contrary, “teacup mini-pigs” soon outgrow teacups, buckets, and even bathtubs when they mature. Another drawback of teacup pets, I would guess, is that they leave a funny taste in the cup, thus ruining your tea.

As it happens, the tiniest and most endearing animals you’ll ever meet are available just about anywhere if you know where to look. Move over, teacup pets – water bears, also known as moss piglets, are more like teaspoon animals. Often called by their Phylum name Tardigrade, meaning slow-stepper, water bears have four pairs of stubby legs, each ending in 4 to 8 claws. With expressive, wizened faces and pleasantly plump bodies that can be transparent, white, red, orange, yellow, green, purple, or black, water bears evoke a psychedelic vibe that belies their toughness. And believe it or not, they’re instinctively paper-trained.

If you’re wondering why you haven’t seen water bears at the pet store, it’s because these Lilliputian livestock are only 0.9 to 0.3 mm long, or in non-metric terms, wicked-small. All the same, they are loaded with character and fascinating to watch. You just need to get your hands on a low-power dissecting (stereo) scope to appreciate them.

Uploaded to YouTube by The Dodo

Comprising more than 1,100 species, tardigrades eat moss, lichens, algae, and occasionally, each other. These critters exist in almost all environments and are true extremophiles, at home in deep ocean vents, boiling-hot mud volcanoes, scorching deserts, as well as on glaciers.

Tardigrades are all-around durable, perhaps more so than any other life form. “When the going gets tough, the tough get going” is a phrase my mom liked to use, but I always thought it meant if the going is tough, you should run away to someplace nicer. When life gets tough for a water bear, its response is to form a cryptobiotic state (that is, a dormant state where metabolism stops) known as a tun. It drains nearly all the water from its cells and pumps in a special sugar called trehalose. It also produces unique damage-suppressing proteins to protect against DNA damage. How much tougher are moss piglets in this dormant state? Tuns more.

Whereas about 500 rads of X-rays would kill a human, tardigrades don’t blink when hit with 570,000 rads, suffering no mortality or even DNA damage. Water bears are known to live for 20 to 30 years in their tun-form, yet after a few minutes of hydration, they carry on where they left off, functioning normally.

Apparently, water bears tolerate cold down to roughly -328oF, close to absolute zero, and have also done just fine in temperatures of 300oF. They can withstand more than 1,200 times atmospheric pressure, as well as the complete vacuum of space. We know this because in 2007, some were taken into low-Earth orbit for 10 days on the Foton-M3 spacecraft.

Studying the cryptobiotic strategies of water bears have allowed researchers to develop so-called dry vaccines based on trehalose instead of water. Dry vaccines are not subject to spoilage, which is a great boon to all those who live in regions where refrigeration is limited.

Another neat thing about tardigrades is that they’re born paper-trained. Well, sort of. Each time a water bear grows a bit, it needs to shed its skin, a process which may be repeated 12 or more times as it matures. Masters of efficiency, they wait until they need to molt before pooping, and leave rows of little pellets lined up inside the old skin. This would make it handy for their owners to pick up when taking their charges to the water-bear park, should such a thing ever come to be. Lifespans vary by species from a few months to a couple of years, not counting time spent in suspended animation.

Water bears can be collected from nearly any moist substrate, particularly moss, and at any time of year. Here’s a link that gives simple instructions for locating your first water bear. A good-quality magnifying glass will work to view them, but it’s more comfortable watching through a dissecting scope. Don’t worry – no dissecting is required.

Please help promote ethical pet ownership: avoid teacup pets, and adopt a tardigrade.

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  1. Fascinating creatures Paul. The Dodo video on these Tardigrades is a great watch. What scientists knew 250 years ago was astounding. The survival in such extreme of extreme conditions and temperatures is mind blowing. I’m not surprised “teacup dogs” or pigs suffer the myriad of problems they do per your provided inks.

    It absolutely is animal cruelty at the most basic level of the animal’s very existence and all the problems they’ll have because some people think their “cute” and will spend a large sum of money to buy them. If I had my way, this would be illegal and a felony, with both the breeders and customers subject to high fines and arrests.

    It would drive it underground, I know, but still hopefully cut it way back. If there’s a will there’s a way, but that way needs to be made hard, and not worth it. If being humane to animals (sadly) isn’t motivation, than it’ll have to be money and police records. Dogs already naturally small are a different story, but always check out the source.


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