The e-mails to the "Water Bear web base" fall into two distinct groups. One group consists of inquiries which might be considered as typical for a popular scientific magazine:

+++ How can I distinguish among different water bear species? +++ Please help! I have been searching for a long time but didn't find any tardigrades at all. +++ What are the appropriate conditions for a water bear culture? +++ Do you have any information about the tardigrade size distribution in southern ... ? +++ May I use one of your images for my publication ... My budget is very limited. +++ Where can I buy water bears? +++ Do you have a species list for ... country? +++ I would like to buy the printed version of the 'Water Bear web base' +++ Is all this reality or just a funny joke? +++ ... etc.

Though less abundant but on a regular basis we receive e-mails which might be considered as surprising or a little bit irregular. Typical examples are:

+++ I believe that some tardigrades live within my body. How can I get rid of them? +++ Do tardigrade live in textiles (Blue Jeans)? +++ How can I kill those tardigrades within my apartment? +++ Are the water bears extraterrestrial beings? +++ ... etc.

The last question about extraterrestrial life seems to be discussed by very different groups of people, also scientists. E.g. there was one link directed to our website in connection with the general topic: "The European Space Agency increases its budget for astrobiology".
Possibly we tend to suspect the existence of extraterrestrial organisms when we encounter beings with extremely unusual properties. In particular the water bears have amazed many people. Even the scientists who claim to be "objective" tend to use somewhat romantic terms when describing the water bears by words. You will find a collection of the respective quotations at  Micscape (The incredible water bear)  .

In fact some of the photomicrographs of water bears look a little bit mysterious.The image below has been taken in dark field illumination without further tricks.

Is this an image of an alien
or just an Echiniscus water bear
in dark field illumination?
(original length about 250 µm).

The water bears seem to be among those few organisms on earth that might travel across the universe without any modification:

-- They can survive high levels of radiocative radiation
-- They can withstand a vacuum (when in dry state)
-- They have no problem with temperatures as low as -273°C
-- They might survive elevated temperatures (100°C) when diving from space into the atmosphere
-- Their dry state persists for many years without food, water and oxygen.

Most organisms are not that much adapted to extreme conditions and certainly wouldn't survive those harsh conditions, not even for seconds.
But the tardigrades might be able to cope with a journey through space. Some biologists count them among the so-called 'extremophiles'.

Other authors have claimed that the tardigrades might have developped on distant planets as evolution wouldn't create those extreme properties without need (see e.g. Vettner, citation below).
Further points mentioned are the lack of clear relations to other zoological phyla and the scarce fossil findings of tardigrades.

Our readers certainly will continue to find points for and against the alien hypthesis. But please, do not take this discussion too serious. You see, just the existence of any organism, no matter whether on earth or elswhere, including yourself has to be considered as a marvel beyond our understanding.

Literature

Vettner, Joachim: The "little bears" that evolutionary theory can't bear!
Creation Ex Nihilo  12 (1990) 16-18.

© 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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