Nature Bulletin No. 7 March 24, 1945
Forest Preserve District of Cook County
Clayton F. Smith, President
Dr. David H. Thompson, Zoologist
A SNAPPING TURTLE, a BLANDING'S TURTLE and two
PAINTED TURTLES were found along the shores of McGinnis Slough
on March 10. They were alive but very sluggish. On March 17, nineteen
snappers, another Blanding and several painted turtles were found alive.
All were very sluggish although it was a warm, sunny day. The two
largest snappers, weighing about 25 pounds each, later died. Numbers
of dead painted turtles were found along the shore. This was unusually
early for turtles to be out.
Turtles and frogs "hole up" for the winter and hibernate in the mud
under the ice. When animals hibernate, their body processes do not stop
completely; they merely slow way down. Some species slow down more
than others but all of them continue to breathe or use oxygen, and their
hearts continue to beat very slowly. Although turtles can remain under
water for long periods in the hot summer, they have lungs and must
come up to breathe air once in a while. So it is with frogs. Both turtles
and frogs must have some oxygen when they hibernate for the winter
under the ice. They get this oxygen by absorbing oxygen, dissolved in
the water, through the membranes of their mouths and throats. Some
kinds of animals may also take dissolved oxygen in through their skins.
When thousands of fish suffocate or "winter kill" due to thick, snow-
covered ice covering the water for a long time, as happened this winter,
sometimes the turtles and frogs smother too. Since it was unusually
early for turtles to be out we may suppose they were roused from their
sleep by partial suffocation. Many floated to the top, got air, were
washed ashore by the wind, and lived. Others died before they got
ashore. The two big snappers were too weak to breathe and live.
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Update: June 2012