Have you ever wondered what wild animals do in the wintertime to survive extreme cold and icy conditions?
Generally the "cold-blooded" animals that cannot generate their own heat can slow way down so they don't need as much food. Amphibians, reptiles and fish will use this method to get through the winter. But most of them do need to find somewhere that is above freezing, even if just by a few degrees.
There is a species of wood frog that has evolved ways to freeze completely solid by moving the water out of its cells where it can turn to ice without damaging the cell. They also produce extra sugars inside the cells that can then hold a small amount of unfrozen water. These frogs can go through many of these freeze-thaw cycles in a winter. Scientists are studying this as a method to preserve organs needed for transplants for longer periods of time.
Local frogs, toads and salamanders can hide underground or deep in mud where they hibernate until spring. They don't eat, so their hearts slow down, and they absorb oxygen through their skin. Snakes, lizards and turtles try to find a protected area to avoid freezing. Some snakes snuggle together to keep each other warm. Even if they could be out in the cold, there would hardly be any insect food available.
Some insects find places to hide while others overwinter as eggs or cocoons. Monarch butterflies use a completely different method -- they migrate. People knew these butterflies flew south in the winter, but scientists did not discover that they flew down to a small area in Mexico until 1974. Of course, the local Mexicans knew the butterflies migrated there every winter.
You can learn about the discovery of the monarch butterfly migration at Carnegie Science Center's Omnimax movie "The Flight of the Butterflies."