|Woolly Bear By Micha L. Rieser (Own work) [CC BY-SA 4.0], via Wikimedia Commons|
This idea was made even more popular in 1948 by a study by Howard Curran, a curator of Entomology at the American Natural History Museum. Curran went to Bear Mountain State Park in NY with several other scientists and collected 15 woolly bear specimens. The study indicated that there was a correlation with the size of the bands and the winter weather. Curran continued the study for several more years. Although at the time the results were popular, further research of much larger sample sizes indicates that there is simply too much variability in individuals of these caterpillars for their predictive powers to be true. Although they might not be able to predict winter weather, they are the stars of many festivals and events, including the Woolly Bear Festival in Vermillion, Ohio and the Woolly Worm Festival in Banner Elk, North Carolina.
The really fascinating fact about these caterpillars is their ability to weather the winter months by freezing themselves solid. Their bodies actually break certain parts down and begin to produce glycerol, which works as an "anti-freeze" to prevent cell damage. The structure of their bristly hair, or setae, allows them to begin freezing on the outside before their bodies freeze.
Although all woolly bear caterpillars, or Pyrrharctia isabella, are capable of weathering freezing temperatures, the ones that live in the Arctic are the most amazing. Due to short periods of warm weather, the caterpillar will go through this freezing and thawing process up to 14 times (in other words, 14 years) before it makes a cocoon and emerges as an adult Isabella Tiger moth!
|Pyrrharctia isabella – Isabella Tiger Moth By Andy Reago & Chrissy McClarren [CC BY 2.0], via Wikimedia Commons|
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- Weather.gov: "Woolly Bear Caterpillar- Weather Predictor or Not?"
- Scientific American Blog: "Arctic Creepy-Crawlies Part II: Woolly Bear Caterpillars"
- Old Farmers Almanac: "Predicting Winter Weather- Woolly Bear Caterpillars"
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