A Hairy Herd
Perhaps not as awe-inspiring as the seasonal migrations of herds in the Serengeti, but possibly more aww-inspiring is the annual scurrying of the woolly bears across roads, sidewalks, and trails. “Woolly bear” is used as a catch-all term for many caterpillars of the furry variety, but in this blog we are specifically talking about the larval form of the Isabella tiger moth. (We are also not discussing woolly bears of the ursine form – it would be an enormous surprise to see a black bear scurrying across a Parklands road.)
Woolly bears are featured in a popular folklore tale (check out our blog about folklore!); the larger the brown band in their center, the milder the coming winter. But don’t base your winter vacation on woolly bears. While science doesn’t quite support this prediction theory, woolly bears can tell us something about the previous seasons. As the caterpillar grows and molts, their segments turn from black to brown. It is also thought that moisture plays a role in coloration; the wetter the season, the browner the woolly bear.
Woolly bear color variation
Two generations of woolly bears are born per year; the first is born in spring, and the second in fall. It is this fall generation that is currently hurrying across seemingly every path in The Parklands. These furry friends are looking for a place to hibernate for the winter. The long hairs on their body will start to freeze, and the caterpillars will hunker down under piles of leaves and bark. Eventually, they will turn into tiny woolly bear popsicles. But never fear – they have a plan in place. Cryoprotectants produced inside woolly bears allow just the right amount of their body to freeze, keeping their organs and cells functioning. As spring arrives and the air warms, our fuzzy friends emerge from their frozen slumber and continue their life cycle.
A side note: Isabella tiger moth woolly bears are not dangerous. Playing dead is their number one defense. However, other species of hairy caterpillars have more painful defenses, and can harm you if they feel threatened. If it looks sharp or scary, it’s best not to touch; instead, observe from a distance. Please remember to always respect wildlife.
The myth of the Woolly Bear: http://www.npr.org/2013/11/08/243950750/
Science Friday: http://www.sciencefriday.com/videos/the-myth-of-the-woolly-bear-2/