Frog in small lined pond

Question
I live near Chicago and have a small (4.5' by 6')pond with a lining.  This year a frog has lived in the pond.  My husband says he needs to hibernate in mud along the side of the body of water, but the pond is lined.  What can I do to help him survive the winter?

Answer
Turtles, not frogs hibernate in the mud.  Frogs prefer crevices in logs, rocks, etc.  It will likely set out to find a proper place when the time is right.  Some species will even hibernate right in the pond, but probably not in Chicago.  Their internal body temperature will reach nearly as low as the air temperature, but survival is very likely.  If your pond freezes over, make sure to punch a hole through the ice to allow for gas exchange.