Mole rat's magnetic magic revealed

22:00 19 January 04

The blind mole rat continually monitors its direction using the Earth's
magnetic field when it makes long underground journeys, new research has
revealed. It is the first animal discovered to have this talent.

Blind mole rats have no eyes and spend most of their time burrowing in
subterranean tunnels. They often have to make long journeys from their nests
to find food and yet are able to find their way efficiently through complex
mazes of tunnels.

They use signals such as smell and balance to check their direction and
progress over short distances. But scientists have now discovered that on
longer routes they combine this information with constant reference checks
of the Earth's magnetic field.

"On long journeys with many twists and turns, it's easy to get lost by
relying only on internal signals. We found that the mole rats used the
external reference of the Earth's magnetic field as an additional tool,"
says Tali Kimchi, at Tel Aviv University, Israel.

Magnetite crystals

Kimchi, with colleagues at the University of Geneva, Switzerland, revealed
the mole rat's abilities by tracking their progress through laboratory mazes
while using magnets to vary the external magnetic field.

Although numerous birds and fish are known to use an internal compass, the
wood mouse is the only other land mammal. And while these creatures simply
use the magnetic field to check their direction before setting off on a
journey, the mole rat is unique in using it to continually check its
progress.

How animals use magnetic compasses is not well understood. But some research
suggests that it relies on magnetite crystals located next to the animals'
olfactory region.

"Even we may have this system," Kimchi speculates. "There
are said to be
people who spend a lot of time in caves, who can find the direction of
magnetic north in the dark."

Journal reference: Proceedings of the National Academy of Sciences (vol 101,
p 1105)

Gaia Vince

>From NewScientist.com
http://www.newscientist.com/news/news.jsp?id=ns99994579

Comment:
The sense, from a subjective perspective, must be like 'smell' or a quality
of smell or odour (as the sensing aparatus is near the olfactory region).

So there really is a sense of direction?

Posted by
Robert Karl Stonjek.
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