How do butterflies survive freezing winters? 

We often see butterflies early in the spring that could not have come from caterpillars. Why don’t the butterflies freeze and die? The Mourning Cloak butterfly hibernates in holes or behind loose bark and before it goes to sleep for the winter, it fills its body with antifreeze. Normal cells are filled primarily with water, but water expands 9% when frozen. This expansion within a cell would cause the cell membranes to break, killing the creature. So the butterfly synthesizes glycerol within its cells, allowing the butterfly’s body to cool to -50F without freezing. In early spring this butterfly re-appears, even before most other insects. The butterfly feeds on the sap of spring trees, which leaks from injuries and buds. 

The Mourning Cloak butterfly also has mostly black on its wings that act like solar collectors absorbing the heat from the sun.

This design feature allows this cold-blooded insect to move around readily in the still cool springtime. This butterfly is not the only one that hibernates – there are several other butterflies and many other creatures that make antifreeze in the fall and hibernate through the winter. 

How did the first Mourning Cloak butterfly learn to make an anti-freeze?

God designed this butterfly to survive the brutal winter as an adult butterfly. The next time you see a butterfly very early in the spring, chances are it is a butterfly that was designed to make antifreeze! 

(Source: Inspired Evidence – Northwood Companion pp.75) “Learn to defend your faith at educateforlife.org“