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
Quoted message said:From NewScientist.com
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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.