The woolly bear caterpillar is a generalist feeder but mostly subsists on vegetation, such as dandelions, plantains and nettles. Following a winter period in which the larva can survive freezing temperatures, the woolly bear caterpillar emerges in the spring to undergo pupation and metamorphize into the Isabella tiger moth.
During hibernation, the woolly bear secretes cryoprotectants, such as glycerol, to prevent bodily cells from freezing. This adaptation allows the woolly bear to endure temperatures as low as minus 90 degrees Fahrenheit. In North American folklore, it is believed that the amount of brown and black in the woolly bear's fur can predict the severity of the upcoming winter.