The woolly bear caterpillar myth dates to colonial times. It goes something like this: Look at the black and brown bands on the fuzzy caterpillar and see which one dominates. If the brown band is wider, the winter will be mild. If the black bands on both ends are larger than the brown, the winter will be colder than normal.
This kind of nonsense would have died out long ago except for the fact that in 1948, an entomologist at the American Museum of Natural History decided that for fun, he would go out and find a bunch of woolly bears and see if the color bands were indeed predictive of the winter weather. The story ran in the New York Herald Times and was picked up by the national press — and the rest is history.
As my fifth-grade teacher used to say, “Let’s put on our thinking caps.” With our “thinking caps” firmly in place, let’s look at the facts of the case. The myth implies that somewhere in the teeny tiny brain of the woolly bear caterpillar is the ability to see into the future and accurately predict climatic events that even the National Oceanic and Atmospheric Administration, with its super-computer modeling based on global climatic patterns, can offer only a “best guess” long-term forecast for the coming winter.
Furthermore, why would woolly bears even care how severe the coming winter is going to be? Woolly bears are among a number of caterpillars, insects and spiders that make glycerol, an organic antifreeze compound that allows them to literally freeze in winter and emerge unscathed in the spring.
In fact, research has shown that the relative length of the black and brown bands in the bristles of the woolly bear is more a function of the age of the caterpillar and the quality if its diet than the particulars of the coming winter.
As for me, I’m going with NOAA and its Climate Prediction Center. They say that La Nina will develop later this fall, resulting in warmer and drier conditions for the Southeast this winter. La Nina is a pool of cooler-than-normal water in the Pacific that affects weather patterns throughout North America.
There is one wrench in the works, and it is becoming a regular feature in our winter-weather pattern. The polar vortex is a powerful mass of extremely cold air swirling around the Arctic Circle. It is typically held in a tight circular pattern, but in recent years it has periodically slowed down and released plumes of arctic air that get caught up in the jet stream, which brings the frigid air down our way.
An intriguing possibility is that one of those slugs of arctic air coincides with a moisture-laden low-pressure system, resulting in an epic snow or ice event, breaking a two-year snow drought for the Southeast.
Sometimes even NOAA gets it wrong, so you’re welcome to consult the woolly bear caterpillar if you like. It won’t be that long before men in top hats will be dragging a hibernating groundhog out of his den to glean the bewildered creature’s weather forecast for the coming spring.
Dennis Chastain is a Pickens County naturalist, historian and former tour guide. He has been writing feature articles for South Carolina Wildlife magazine and other outdoor publications since 1989.
