Round tubs teem with live fish for sale since carp is the
traditional centerpiece of the Christmas feast in much of
central Europe. Oddly enough, when contained in these round
tubs, the carp tend to align themselves with an invisible north-
south line. One might assume this is because the fish are
seeking Santa in his North Pole home, but scientists argue the
behavior is the result of a previously unknown capacity to
perceive geomagnetic fields. This detection of the Earth’s
magnetic poles is a well-studied phenomenon in birds and other
migratory species. These animals travel long distances north and
south every year based on a compass that scientists typically
explain with the pull of the planet’s magnetic poles. But no one
had thought to explore this phenomenon in carp until the
researchers noticed the curious behavior of fish at the market.
The large numbers of carp in their pre-Christmas tubs provided a
perfect set-up for a larger scientific analysis, which looked at
over 14,000 carp from 25 different mark