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Σάββατο 1 Φεβρουαρίου 2014

Uncovering the Secrets of Mole Motion


                                  ScienceTake: τυφλοπόντικες on the Move


http://www.nytimes.com

The question of how moles move all that dirt when they 
tunnel just under the surface of lawns has never attracted 
the extensive study that other forms of locomotion 
— like the flight of birds and insects, or even the 
jet-propulsion of jellyfish — have.
But scientists at the University of Massachusetts 
and Brown University have recently been asking exactly how, 
and how hard, moles dig.
Yi-Fen Lin, a graduate student at the University 
of Massachusetts, reported at a recent meeting of 
the Society for Integrative and Comparative Biology 
that moles seem to swim through the earth, 
and that the stroke they use allows them to pack 
a lot of power behind their shovel-like paws.
Ms. Lin measured the power of hairy-tailed moles 
that she captured in Massachusetts and found they 
could exert a force up to 40 times their body weight.
She also analyzed and presented X-ray videos taken 
of moles in a laboratory enclosure tunneling their 
way through a material chosen for its consistency 
and uniform particle size: cous cous.
Angela M. Horner recorded the videos while studying 
the movement of Eastern moles in the lab 
of Thomas Roberts, a professor at Brown.
One reason moles have not been studied as much as 
some other animals may be that they are not easy 
to capture or keep in a laboratory.
“People said, ‘You won’t be able to catch them and 
you won’t be able to keep them alive,’ ” said 
Elizabeth R. Dumont, an evolutionary biologist who 
is Ms. Lin’s dissertation adviser.
Ms. Lin solved the first problem by camping out in mole 
territory, on golf courses and farms, and marking their 
tunnels with sticks that she would watch for hours until 
movement indicated a mole on the move.
She would then run ahead and block the tunnel by 
sticking a shovel in the ground, and go behind the mole and 
use another shovel to dig the animal out.
As for maintaining the creatures, their high metabolism 
was the problem. 
They need to eat their body weight in food every day 
or they can die quickly.
The diet that satisfied their energy needs, Dr. Dumont said, 
included earthworms, mealworms, eggs and sunflower seeds. 
It worked so well, she said, “we had to put a couple 
of them on a diet.”




Launch media viewer
Despite its small size, a mole can dig through the 
soil with considerable force. Yi-Fen Lin/University 
of Massachusetts, Amherst

Correction: January 28, 2014 
An earlier version of this article misstated an affiliation 
for one of the researchers. Angela M. Horner studied the 
movement of Eastern moles in the lab of Thomas Roberts, 
not Elizabeth Brainerd, at Brown University. 
The article also misstated the name of a species of mole 
that was studied. 
They are hairy-tailed moles, not hairy moles.

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