Monday, October 02, 2006

Cataglyphis introduced by Sir David Attenborough

Via: VideoSift

I found this great video sequence from The Trials of Life documentary about Cataglyphis. David Attenborough gives a nice introduction to the orientation of Cataglyphis in the Sahara. These desert ants use a celestial compass to find their way in this featureless landscape.
But this is not the end of wonders that the orientation of Cataglyphis has to offer. As recently published in Science Cataglyphis additionally uses an internal "step counter". From the abstract:
Desert ants, Cataglyphis, navigate in their vast desert habitat by path integration. They continuously integrate directions steered (as determined by their celestial compass) and distances traveled, gauged by as-yet-unknown mechanisms. Here we test the hypothesis that navigating ants measure distances traveled by using some kind of step integrator, or "step counter." We manipulated the lengths of the legs and, hence, the stride lengths, in freely walking ants. Animals with elongated ("stilts") or shortened legs ("stumps") take larger or shorter strides, respectively, and concomitantly misgauge travel distance. Travel distance is overestimated by experimental animals walking on stilts and underestimated by animals walking on stumps.
"Manipulating the lengths of the legs" is an interesting formulation. Find out what it means by reading the original article. A PDF can be found on the homepage of RĂ¼diger Wehner who spent quite some time in his life to study orientation in desert ants.

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