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Water bears (tardigrades, the Latin term "tardigrada" meaning "slow walkers") are extremely strange microscopic animals. Though almost completely unknown to humans - just have a try and ask your neighbour -, they can be found virtually everywhere: on the ground of the oceans, under massive layers of ice, on top of the Himalayas, in hot fountains, on meadows, in forests and - you can bet on it - close to you, no matter where you live. A small droplet of water is an apartment, possibly even a universe for a water bear.

When seen under a microscope it becomes obvious that water bears are marvels of miniature life:


Water bears - a first visual impression (real size of this animal ca. 0.3 mm)

When the "apartment" water droplet evaporates, tardigrades are able to form extremely durable dry states, so-called tuns. Even after many years small traces of water are sufficient to convert those dry tuns back into living animals, within a few minutes. This is the reason why one of the most prominent water bear species,  macrobiotus hufelandi  was named after the famous surgeon Hufeland who had published about the art of prolonging life.
The biological relations of tardigrades to the rest of the living world are still subject to discussion among biologists, but at least there is some molecular evidence that tardigrades are definitely not extraterrestrials. The zoological group of 750 known water bear species even received the high honour to get a tribe name of its own. Please keep in mind that there are only about 30 phyla in zoology overall.

The first and even illustrated observation of a water bear was published by the German clergyman J.A.E. Goeze in 1773:

[tardigrade tardigrades water bears]

Goeze's water bear portrait (1773)

The small video clip below shows the enormous grace and muscle control of the water bears. Overall they have eight (!) legs, but under the microscope you will perceive a lower number at the first glance because some of the legs are hidden behind the baroque body. When looking closer you will see also claws, eyes, mouth, stomach ...
The animal shown here is an inhabitant of Bavaria (Germany).


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Tardigrades are a fascinating subject, also for educational purposes, not only for the biological education at school level but also for grown-up people. Water bears can be

- found easily next door
- transported and stored in dry state
- revived at any time, whenever you like
- studied even with a modest microscope

Last but not least the water bears still guard many secrets to be explored, also by amateur scientists. E.g. there are reports in the scientific literature about mating habits of water bears resembling in a funny way to those of humans ...

When looking closer the tardigrades reveal more and more marvels. The image below represents a tardigrade egg, only one of many many different species. There are eggs with a fascinating polygone structure, with high levels of symmetry and sophistication. In the final stage of development the eggs are becoming more and more transparent so you can follow the growth and increasing life activity in the eggs under your microscope. Below you will find an image of an egg of the water bear Macrobiotus richtersi :


Tardigrade egg. Real size about 0.08 mm

In issue no. 2 we will unveal the most promising types of localities where you can expect to find water bears and explain the procedure how to study them without being a water bear killer. Water bears need a spaceholder between the object slide and the cover glass, so take care not to exert undue pressure on their bodies.
And remember: There are only very few, if any subjects in biology which are as fascinating and interesting as those tiny water bears.

© 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.

Recommended literature (further titles will follow later)
Ernst Marcus: Bärtierchen (Tardigrada). Gustav Fischer Verlag, Jena 1928.
Ian M. Kinchin: The Biology of Tardigrades. Portland Press, London 1994.
Hartmut Greven: Die Bärtierchen. Neue Brehm-Bücherei, Wittenberg, 1980.
Giuseppe Ramazzotti: Il phylum Tardigrada. Mem. Ist. Ital. Idrobiol., Band 28 (1972) S. 1- 732.

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