TURTLES SWIM UNDER ICE
by Whit Gibbons
February 12, 2006
you believe global climate change is real or not, my winter so far has
been warmer than usual. A cold winter makes spring a more rejuvenating
experience. This was especially true at the end of a memorable winter
many years ago in Michigan as I stared into icy waters looking for life.
Any kind of life.
work with reptiles, I found Michigan winters excessively long. Being a
herpetologist is not a prerequisite for having this attitude, but someone
interested in reptiles is unlikely to find much of interest amid ice and
snow. By early April of that year, the winter had gone on long enough
to suit me. I wanted to see a lake without ice. Nevertheless, when someone
phoned to say that a turtle had been seen swimming beneath the ice in
open water around a boat dock, I ventured out to the icy lake.
"knew" that turtles were not active in cold weather. Therefore,
we wasted no time looking for turtles in half-frozen lakes. But the day
was sunny, in fact brilliant, and by my Alabama standards the winter had
overstayed its welcome by several weeks. I was anxious to see my first
reptile of the year; even a single, disoriented painted turtle would be
a welcome sight.
clear water surrounded the wooden dock. The open water stopped at the
edge of the ice shelf that covered the remainder of the lake. I was disappointed.
The lake was not really accessible; only a few hundred square feet around
the dock had thawed. But the sky and the water were clear, so I decided
to take a look. Standing in the bow of a cold aluminum boat, I pushed
out into the water and used one oar as a pole to push along the shoreline.
Seconds later I saw a painted turtle swimming along the bottom of the
lake. I used my dip net, turning my first reptile sighting of the year
into my first capture: a male painted turtle, its black shell margined
with crimson, its black head and legs adorned with bright yellow stripes.
A handsome creature, and amazingly active for a reptile in ice water.
I assumed this was an aberrant animal as anxious to rush the season as
While I was
putting the turtle into a collecting bag, the boat was assisted by a cold
draft of late winter wind and drifted across the open water toward the
ice shelf. I peered into the crystal clear, pristine waters. The ice at
the shelfs edge was like a glass counter. I stared and marveled.
Turtles. Dozens of painted turtles. Crawling. Moving. Swimming along the
bottom beneath the transparent ice shelf. The scene brought a rush of
emotional warmth in stark contrast to the physical world of frigid water,
freezing air, and ice-encrusted lake.
of the phenomenon I had stumbled on was not particularly profound. I concluded
that the turtles were trying to raise their body temperature on what was
probably their first view of the sun in months. One reason for trying
to get warm enough to be active when the lake is still ice-covered may
be related to their breeding season. Whatever the case, the painted turtles
had taken advantage of the opportunity to raise their body temperature
and were active under near-freezing conditions.
my amazement, and the unneeded reminder that Michigan is cold much of
the time, came the realization that I had witnessed a heretofore unknown
phenomenon. The observation inspired me to write my first technical publication
in a scientific journal. I viewed publishing as a sacred ritual, and seeing
the paper appear in a reputable scientific journal gave me a confidence
I had lacked. I could actually observe a herpetological phenomenon and
write about it for other people to read. The event also confirmed for
me that reptiles are remarkable and mysterious. But perhaps the most important
lesson was one that has continued to be part of my learning experiences.
That is, animals do not always do what our preconceived notions prepare
us for, and they can offer us biological mysteries we did not even know
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