Water Bears belong to a lesser known phylum of invertebrate animals, the Tardigrada. The first tardigrades were discovered by Goetz in 1773. Over 400 species have been described since that time.

Tardigrades grow only to a size of about 1mm, but they can easily be seen with a microscope. Tardigrade bodies are short, plump, and contain four pairs of lobopodial limbs (poorly articulated limbs which are typical of soft bodied animals). Each limb terminates in four to eight claws or discs. They lumber about in a slow bear-like gait over sand grains or pieces of plant material.

Tardigrade facts.


Behold, The Mighty Water Bear!

Tardigrades, aka Water Bears, are a type of extremophile, a name that’s well-deserved. Tardigrades are able to go into what’s called a ‘tun state’ where they become virtually invincible. They’ve survived the vacuum of space and extreme radiation, they’ve been dried out and resurrected decades later, they handle boiling temperatures and deep freezing down to 1 degree Kelvin (molecular motion stops at 0 degree Kelvin) and they’ve managed to look adorable and cuddly while doing it! Basically, Water Bears are the most badass microorganism around. Don’t mess with Water Bears.

Get more info and see the full video via Sci Fri


A tardigrade has been brought back to life after being frozen for 30 years

In 1983, Japanese scientists accidentally scooped up two tardigrades and an egg when they were collecting a sample of moss. Scientists stored the organisms at minus 4 degrees Fahrenheit. One tardigrade and the egg lived and are now slowly coming back to life. Could this lead to breakthroughs in cryonics?

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A tardigrade (waterbear) hatching. 

Tardigrades reproduce sexually and females lay eggs. She’ll actually shed her skin first and then lay her eggs inside of it. The babies then hatch from their eggs and then have to crawl out of the skin husk. Fun fact: tardigrades are born with the same number of cells as their adult counterparts - their cells just get bigger as they age. 


Inside the Bizarre Genome of the World’s Toughest Animal

Tardigrades are sponges for foreign genes. Does that explain why they are famously indestructible?

by Ed Yong

The toughest animals in the world aren’t bulky elephants, or cold-tolerant penguins, or even the famously durable cockroach. Instead, the champions of durability are endearing microscopic creatures called tardigrades, or water bears.

They live everywhere, from the tallest mountains to the deepest oceans, and from hot springs to Antarctic ice. They can even tolerate New York. They cope with these inhospitable environments by transforming into a nigh-indestructible state. Their adorable shuffling gaits cease. Their eight legs curl inwards. Their rotund bodies shrivel up, expelling almost all of their water and becoming a dried barrel called a “tun.” Their metabolism dwindles to near-nothingness—they are practically dead. And in skirting the edge of death, they become incredibly hard to kill.

In the tun state, tardigrades don’t need food or water. They can shrug off temperatures close to absolute zero and as high as 151 degrees Celsius. They can withstand the intense pressures of the deep ocean, doses of radiation that would kill other animals, and baths of toxic solvents. And they are, to date, the only animals that have been exposed to the naked vacuum of space and lived to tell the tale—or, at least, lay viable eggs. (Their only weakness, as a researcher once told me, is “vulnerability to mechanical damage;” in other words, you can squish ‘em.)…

(read more: The Atlantic)

images: Boothby at al, Bob Goldstein and Vicky Madden, UNC Chapel Hill, Willow Gabriel and Bob Goldstein, http://tardigrades.bio.unc.edu/

Meet the tardigrade—a tiny, nearly indestructible creature, and one of the stars of the upcoming exhibition, Life at the Limits: Stories of Amazing Species, opening 4/4.
Typically found near water, tardigrades can survive just about anywhere, from the bottom of the ocean, to a Himalayan mountain, to the surface of a glacier. “They can survive the loss of almost 100% of their water,” said Dr. Mark Siddall, a parasitologist and curator of the upcoming exhibition. Tardigrades even survived when they were blasted into space and left outside in the subzero, oxygen-deprived vacuum for 10 days.
Pictured is Paramacrobiotus craterlaki, a carnivorous tardigrade found living in moss at a crater lake in Kenya. 

Learn more about tardigrades in a recent buzzfeed story, and read all about the upcoming exhibition, Life at the Limits

Image: Eye of Science/Science Source

A Frozen Tardigrade, aka Water Bear, Has Been Brought Back to Life After 30 years!

And it hatched out 14 healthy babies…

by Bec Crew

A tardigrade that had been frozen solid for more than 30 years has been brought back to life by researchers in Japan, and has gone on to produce 14 healthy babies.

That’s record-smashing stuff right there, because before this tough little water bear came back to life, the world record for reviving a frozen tardigrade was nine years.

The researchers also thawed out an egg that was collected and frozen with the tardigrade in 1983, and not only did a healthy baby hatch from it six days later, but it went on to successfully produce offspring of its own…

(read more: Science Alert!)

photograph by Megumu Tsujimotoa et. al.


Water bears (or tardigrades) are tiny invertebrates that live in aquatic and semi-aquatic habitats such as lichen and damp moss. They require water to obtain oxygen by gas exchange. However, in dry conditions, they can enter a cryptobiotic state of dessication, known as a tun, to survive. In this state, water bears can survive for up to a decade. 

Water bears are found throughout the world, including regions of extreme temperature, such as hot springs, and extreme pressure, such as deep underwater. They can also survive high levels of radiation and the vacuum of space. 

[1] Water Bear welcomes you.

[2] Water bear tun
(Milnesium alpigenum - formerly Milnesium tardigradum). Color enhanced scanning electron micrograph (SEM) of a water bear in its dormant state, known as a tun.

Milnesium alpigenum is a carnivore that feeds on nematodes, rotifers and protozoa. This specimen originated from moss samples in Tubingen, Germany.

Magnification: x833 when viewed 10cm wide  |  (via Science Source)

[3] Egg of water bear Paramacrobiotus richtersi
color enhanced scanning electron micrograph (SEM).

This egg was found in moss samples from Tubingen, Germany.

Magnification: x833 when viewed 10cm wide  (via Science Source)

[4] Egg of water bear Macrobiotus sapiens
close up color enhanced scanning electron micrograph (SEM).

This egg was found in moss samples from Croatia.

Magnification: x4800 when viewed 10cm wide. (via Science Source)

[5] Egg of water bear Paramacrobiotus kenianus.
Color enhanced scanning electron micrograph (SEM)

This egg was found in moss samples from Kenya.

Magnification: x3333 when viewed10cm wide (via Science Source)

[6] Water Bear says goodbye as you go to the next post.