Author Archives: Kristin S.

Why Did the Woolly Bear Cross the Road?

Fall brings with it the familiar and well-loved sight of woolly bear caterpillars crossing roadways and sidewalks. Looking like orange and black-banded bottle brushes, these 1-2 inch caterpillars dodge vehicles and bicycles to get to the other side.

With luck and time, these beloved caterpillars will transform into Isabella Tiger Moths, a yellowish-brown moth not nearly as cute as its immature form.


Woollys in Winter

Woolly bears are one of the few caterpillars to overwinter as caterpillars, risking freezing temperatures and predation to emerge in the spring. Quite simply, woolly bears crossing roadways are risking life and legs to find the perfect leaf litter, the perfect board, or the perfect pile of wood chips under which to hibernate. They need a spot sheltered from drying winds, a bit of moisture, and cover from predators.

When they find that spot, they curl up in a tight ball and settle in for a long winter. Their bristle hairs are a deterrent to predators (although raccoons have been observed brushing the hairs off and then eating these insect delicacies). The spiky ball shape makes the caterpillars slippery to predators. If you try to pick up a woolly bear in its hibernating pose, you may find it slips from your grasp.

Woolly Bear

Come Springtime

If a woolly bear survives a New England winter, it will emerge in the spring very hungry. At this time of year, you may see caterpillars wandering again as they search for food plants. The caterpillar eats for a short while and then spins a cocoon, made of bristle hairs held together with silk, in a protected spot under rocks or bark. In two weeks, an Isabella Tiger Moth emerges from the cocoon.

The cycle begins again when the female Isabella Tiger Moth lays clusters of eggs on a variety of hostplants. Favorites include dandelion, grass, meadowsweet, nettle, and more. Eggs hatch in 4-5 days, and the young caterpillars feed in groups, becoming solitary as they grow older. Over 3-4 weeks, the caterpillars undergo 6 molts, or skin sheddings, and it is the second generation each summer that will cross roads to find that perfect overwintering spot.

Fun Facts about Woolly Bears

  1. Woolly bears are very fast (for a caterpillar, at least). They can travel up to 4 feet per minute, which is roughly equivalent to .05 miles per hour.
  2. Contrary to folklore, the woolly bear is not an accurate weather forecaster. Does the width of its orange band predict the severity of the oncoming winter? No. Instead, each time the caterpillar sheds a skin, its orange band grows a bit larger. So, broader orange bands are most likely an indication of the age of the caterpillar, not of future winter weather.
  3. Banner Elk, North Carolina has been celebrating the Woolly Worm Festival since 1978. During the “Woolly Worm Race,” pet woolly bears race up a 3 foot long string. The winner becomes the official predictor of winter.

Have You Hugged a Hemlock Lately?

Richard Webb, Self-employed horticulurist, Bugwood.orgOf all the evergreens in the winter woods, eastern hemlocks are the friendliest.

During the short, dark days of winter—when we are tempted to stay inside our heated spaces—the hemlock calls us to come out and play.

Treasured Tree
What makes the eastern hemlock so special to winter-weary humans?

  • Its short, flat needles are soft to the touch (not prickly like spruce) and its trunk doesn’t gum up your hands with pitch.
  • Hemlocks are shade loving and their lower branches can live for a long time, making them the perfect trees for finding or building shelters made of sticks and leaves.
  • A mature hemlock creates such dense shade, and its needles cause the soil to be so acidic, that few other plants can grow underneath. As a result, hemlock groves create their own micro-environment—cool, open, and dark. Perfect places for hiding, resting, and playing games.

Wildlife Treat

Porcupine in Hemlock_Richard JohnsonHemlock groves are magical to non-human animals, too. Because hemlock branches hold so much snow, snow depths beneath the trees are significantly lower. Deer often bed down underneath these trees, taking advantage of shallower snow and sheltering branches. Treat yourself to an early morning snowshoe or hike. You may be able to follow deer tracks from hemlock to hemlock, finding packed snow outlining the shape of a deer underneath each one.

Many animals eat hemlock. (In case you were wondering, eastern hemlock is not the kind of hemlock that poisoned Socrates.) Grouse and rabbits eat buds and needles. Red squirrels and mice chew off the scales of the tiny hemlock cones to get at the seeds underneath. Deer will also eat hemlock foliage and twigs as high up as they can reach.

Porcupines prefer hemlock and will eat the bark and chew off large twigs. If you see scattered hemlock twigs or tips in the snow, look up. You may see a porcupine in the branches of the tree or, on at least one Mass Audubon wildlife sanctuary, living in the tree’s trunk.

The Fate of Hemlocks

Chris Evans, Illinois Wildlife Action Plan, Bugwood.orgSadly, our Massachusetts hemlocks are threatened by woolly adelgid, an aphid-like insect that sucks sap from the needles. If you see what look like tiny white cotton balls at the base of hemlock needles, you’ll know the tree is infested. Woolly adelgid can be killed by very cold winters or pesticides, and scientists are experimenting with biological controls, but currently there is no cure.

Warming temperatures encourage the spread of woolly adelgid, so we can help hemlocks by combating climate change. Find out how Mass Audubon is leading by example and how you, too, can reduce your carbon footprint.

Finding Hemlocks

Many Mass Audubon wildlife sanctuaries harbor hemlock groves, including Eagle Lake in Holden, Laughing Brook in Hampden, Pleasant Valley in Lenox, and Wachusett Meadow in Princeton.

Tread lightly. Approach quietly. Appreciate much. But go out and find a hemlock today, for there is no better friend in the winter woods than the eastern hemlock.

Learn more about winter trees in a Mass Audubon program.

Photos Richard Webb, Self-employed horticulurist,;
Richard Johnson;  Chris Evans, Illinois Wildlife Action Plan,