Book 4, Question 32
Why Do Worms Come Out After Rain?
Wet ground fills the worm's tunnels with water. Worms breathe through damp skin, and coming up is often easier than staying in a flooded tube. Rain is also a good time to travel!
From the book
Page from A Million Whys Book 4
More fun facts
- Worms breathe through their skin, which needs to stay moist.
- A worm can even survive underwater for several days.
- For years, scientists thought worms came up after rain only to avoid drowning in flooded tunnels.
- Newer ideas suggest worms may surface because wet ground makes it easier to travel, or to escape predators.
- Vibrations like those of a digging mole can make worms rush out of the ground, and some bait collectors use this trick, called worm grunting.
- After crawling for a while, worms burrow back down, which can take from 10 minutes to more than an hour.
Sources: National Park Service, Scientific American, Science News Explores, Scientific American
Questions kids ask
Do worms drown in the rain?
Usually not. Worms can survive underwater for days, so scientists think they come up for other reasons.