Sunday, May 24, 2009

Hairy Stomachs

TV wildlife documentaries tend to focus on large animals with fur or feathers, but most of the animal world is tiny and many of the microscopic life forms that live in the water or in soil, that play a vital role in the functioning of ecosystems, are poorly understood. This animal is a gastrotrich – a name that literally means ‘hairy stomach’, on account of the tiny beating hairs on its underside that propel it through the water. These restless little animals, none longer than half a millimetre, are in every pond and also occur in marine environments, but compared with larger life forms we know very little about the lives of the 400 or so species that have been discovered so far. If you have a garden pond, or any water in the garden that contains decaying vegetation, there’ll be gastrotrichs in it, along with the heliozoans and rotifers that I mentioned in earlier postings. Gastrotrichs are fast moving, endlessly exploring detritus in the water in search of a meal, and defend themselves with tiny spines on the body surface. I used DIC optics again for these pictures, to highlight the animal’s spiny covering.


  1. Hi Phil. I really enjoyed reading this and your earlier postings on heliozoans. If there's a chart of top blogs anywhere, this gets my vote!

    The mammal/bird bias you raise is, I suppose, understandable - but you don't have to go to the microscopic level to be struck by how little we know once you cross the fur/feather boundary. Even trying to find reliable and consistent information about something as basic as the life cycle of a common or garden fly isn't that easy (e.g. see my posting about the noon-fly

  2. Thanks Nyctalus, After some searching I think I might have found a source of info about the noon-fly's breeding habits...have left a message on your blog. I bet that somewhere in the Victorian and Edwardian naturalists' literature there's an account of noon-fly natural history, but because such journals are rarely digitised and so aren't available on the web, and almost no one reads old journals these days and libaries are dumping them, we'll probably never know unless we research it ourselves.....

  3. Hi,
    What kind of microscope do you use to capture these gorgeous photos? Is it a binocular compound? What is the magnification power?
    I am thinking of buying a microscope, and hoping it could have a similar power as yours.

  4. Hi Pamela,In this case it was a rather expensive Nikon research microscope that I use for my work but you can easily see these little animals with an inexpensive binocular compound microscope with a magnification of x100


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