Temperature and Survival A Balancing Act “Since monarchs (and other insects) are cold-blooded, they do not use much energy when they are in a cool environment,” says Dr. Karen Oberhauser. Learn what it means to be cold-blooded: >> More Cold-Blooded Facts About Monarchs Why do monarchs move so slowly in cold temperatures? Their muscle activity depends on chemical reactions that go slowly when its cold and quickly when its warm. Monarchs are paralyzed by cold temperatures. It must be at least 41 degrees F for them to crawl and 55 F to begin to fly. Monarchs sometimes shiver (move wings rapidly) to warm up the muscles inside. Learn more about when and why monarchs shiver.   Copyright 2006 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to our feedback form