Florida Lobster Navigation
Keys Treasures
obtain it, who nevertheless are happy to eat seafood. And high on the
list, for some of them, is a delicious lobster. After all, just look at
it. Can you imagine anything more primitive, anything less likely to
have a conscious sense of its own existence? Well, next time you sit
down for a lobster dinner, ponder this: You will be tucking in to one
of nature's most accomplished navigators. For the fact is, the common
lobster has a geographical location system that humans can match only
with the latest, most sophisticated version of GPS, the hugely
expensive navigation system that depends upon satellites that orbit the
earth, the most accurate timekeeping devices ever devised, masses of
computer power, and a pile of advanced mathematics.
What humans accomplish with mathematics and technology, the lobster
achieves by being able to "see" the Earth's magnetic field. Not merely
in the sense of detecting the magnetic poles. The lobster's system is
much more sophisticated than that. The Earth's magnetic field varies
from one place to another, in direction, angle to the Earth, and
intensity. The lobster appears to be able to use this variation to
determine exactly where it is. This was discovered only a few years
ago, by ocean scientist Ken Lohmann of the University of North Carolina
and his Ph.D. student Larry Boles.
It took Bolas six years of study of the Caribbean spiny lobster in the
waters near the Florida Keys before he was convinced that they had this
amazing ability. To demonstrate the fact, he tried all kinds of ruses
to confuse them. He removed them from the ocean and put them in a
lightproof plastic container, drove them around in circles in his boat,
took them ashore and drove them around in the back of his pickup truck,
placed them next to powerful magnets to distort the Earth's magnetic
field, and then dropped them back in the ocean in a new location. As
soon as they were released the lobsters headed off directly towards
their home. They did so even when Bolas placed rubber caps over their
eyes, so they were not navigating by light. But to be doubly sure,
Bolas put some lobsters into a marine tank in his lab and subjected
them to an artificial magnetic field that mimicked that of the Earth.
The lobsters headed off in exactly the direction they would have had to
follow to get home if the field had been the Earth's natural one.
The researchers suspect that the lobster's navigational ability may
make use of small particles of magnetite, an iron oxide, located in two
masses of nerve tissue toward the front of the creature's body. But
whatever the mechanism, now you know that lobsters are born with some
pretty sophisticated built-in navigational abilities, do you still
fancy that lobster dinner?