Tardigrades - just a funny joke?

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Some time ago we received an e-mail by a pupil who had been laughed at by his biology teacher who didn't believe in the existence of tardigrades

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Teenagers have asked us how to clean their jeans from tardigrades and whether tardigrades might cause itching

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An other reader comes up with the question: tardigrades - a new hoax?

So, it appears that we have definitely to clarify some facts here:

Tardigrades (water bears) are real: but how to prove their existence ?

Tardigrades are widely unknown to the public including many scientists and, strange enough, even some biologists. But when looking up the term 'tardigrade' in a good encyclopaedia you will usually find a small entry at least.
Tardigrades are strange microscopic, multi-cellular animals. About 750 species are known to the scientific world. They always live in water: in the oceans and in ponds but most typically in small droplets of water bound by mosses or lichens. So you can bet that some tardigrades will be very close to you, usually in a distance of less than 10 meters !
In order to prove their existence to anybody you might proceed as described in our  introductory chapter  on tardigrade collecting and simply present a few living tardigrades. Most schools do have microscopes which as a rule can be used for a demonstration.
Some people are easily convinced by  photographs  or  videos , but as we all know, nowadays a digital photograph or a video might be a fully synthetic product far from reality.

Tardigrades are harmless

We do not have a single report about a tardigrade seeking human contact or annoying somebody, e.g. by biting into a person's skin.

Why are the tardigrades so much fascinating?

They are so much miniaturized, everything being smaller by a factor of 1000 when compared to humans or mammals but they still resemble so-called higher animals like lizards or as their name indicates, even bears.

Water bear in full movement, exploring a tiny water droplet.
Body length ca. 0.3 mm.

Even after the invention of the microscope it took some time until the first tardigrade was found - in the 18th century, by a German pastor, an early microscope amateur.
Water bears have miniature legs, claws, muscles, eyes, stomach, mouth and nerves. The relative size of a water bear is demonstrated  here .
Water bears show signs of youth  and  high age . There are both sexes and sexual behaviour as well.
Water bears have the strange ability to dry out fully and to  come back to active life  just by means of a droplet of water!
Perhaps it was not the full truth that tardigrades have not been annoying humans: zoologists desperately tried to fit the tardigrades somewhere into the zoological system but in the end resigned and gave them a phylum of their own, which is really an honour when keeping in mind that e.g. the big group of vertebrates has been devalued to a lower taxonomic ranking.
Though tardigrades like to spend their leisure time on the bottom of the oceans, in glacier holes, hot springs and on top of the Himalayas, you will find them also in the cities, in the humble green between the pavement stones - you do not need to travel far to find them.

In short: is there something special about water bears?

Water bears

- are real
- are very small (typically 0.3 to 0.5 mm) but not primitive
- have a precise muscle control and move like higher animals
- resemble little bears; some have claws like cats
- have a mouth, head, brain, legs, eyes, nerves, muscles ...
- live next door to you (for sure)
- are thought to be extraterrestrials, at least by some authors
- have strange eggs which look like miniature artwork
- can transform into a dry state which return to life after years
- in dry state need only a drop of water to revive
- in dry state survive acid and solvent attack
- in dry state survive very high and very low temperatures
- in dry state survive high pressure and radioactive radiation
- have been found under 5 m layers of ice
- have been found in oceans 6000 m below the surface
- have been found on mountains, 6000 m high
- are a phylum (!) of its own
- are fascinating to look at under a microscope
- in return seem to look at you from under the microscope
- are a fine topic for biology courses
- are unknown to most of your neighbours, even to some biologists
- have escaped exploitation by man for centuries

© Text, images and video clips by  Martin Mach  (webmaster@baertierchen.de).
Water Bear web base is a licensed and revised version of the German language monthly magazine  Bärtierchen-Journal . Style and grammar amendments by native speakers are warmly welcomed.

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