“Why do worms come out onto the street when it rains?
It seems to happen more in the spring but it’s been raining for 24 hours and I haven’t seen any yet…”
While it may be raining cats and dogs, it’s usually the worms that come out to play. A heavy downpour can often trigger a mass exodus of earthworms crawling on our streets, driveways, and yards.
Contrary to popular belief, worms don’t surface to escape drowning. In fact, they can survive under water for several days as long as there is enough oxygen. That’s because earthworms breathe through their skin, unlike us. But if the surroundings get too hot, their skin can dehydrate, putting them at risk of drying out. For this reason, the sun is their biggest threat.
Since their surroundings must be moist, earthworms are generally confined underground. However, the wet, humid conditions of a rainstorm provide the perfect opportunity for mating and travel. Earthworms take this chance to migrate overland and can trek much farther using this route than if they had tunneled through the soil.
Scientists also believe the pitter-patter vibrations caused by raindrops can mimic the vibrations created by moles, a common predator. As a result, worm sightings could be due to an underground evacuation.
But whatever the motive may be, it is clear that earthworms save their big entrance for a rainy day.
Answer by Ansel Oommen
Question from Linda via website