THE STAR (Toronto, Ontario) 22 October 06 The single-minded turtle (Peter Calamai)
Let's imagine that while out in the forest in Nova Scotia a few years ago you happened to look down and saw a strange sight: a good-sized turtle stumping along as a fine thread unwound from three bobbins duct-taped to its shell.
Yes, it was a scientific experiment, and the findings are revealed in the current issue of the Canadian Journal of Zoology. The researchers discovered that eastern painted turtles have an internal compass but they don't have a map.
In other words, these mobile thread-dispensers walked in relatively straight lines during their 24 hours, but they didn't tend to head toward lakes in the vicinity. The path trod by the turtles was plotted by using GPS receivers and following the tattle-tale thread.
This result surprised Professor V.O. Nams of the Nova Scotia Agricultural College and graduate student Iain Caldwell, chief turtle-handler.
When semi-aquatic turtles are stranded in unfamiliar territory, as these 60 were, finding water quickly is the way to stay alive.
Moved to an unfamiliar site, for instance, Florida cooter turtles can successfully line themselves up toward a concealed lake 400 metres away.
The eastern painted can track back to its home lake from as far as a kilometre-and-a-half off, but it couldn't locate unfamiliar lakes as near as 100 metres.
Why? Because it doesn't need to, speculate Nams and Caldwell.
Turtles like the Florida cooter live in temporary bodies of water and have evolved ways to find their way to new aquatic digs. But the lakes inhabited by eastern painted turtles tend to be far more permanent.
So they can maintain a direction with internal compass mechanisms but they can't choose one over another. Sounds like some politicians Micro knows.
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