Not the answer you are expecting.
Lucky folks have seen mobs of worms on the sidewalk after it rains. It’s crazy how many worms are all over the parking lots and in the street. The classic explanation is that rain flooded their worm hole and they had to crawl out to avoid drowning. I argue that the flooding story is just a fable, it makes sense and sounds right, right? I say, ‘Wrong’. Try my explanation instead, see if it makes more sense.
My goldfish tank shows that they don’t mind a flood of water. I dropped in a few worms as a snack, but some lucky red wigglers avoided getting eaten by my fish. They sank to the bottom and burrowed into the gravel. I found them months later while vacuuming the tank. Clearly the water holds enough oxygen for fish and worms. Nobody was drowning.
Instead, I say, those crawling worms are on a mission. Think about their usual life in a hole. It gets lonely down there. And when they come to the surface to mate, they only find their nearest neighbors (again). But evolution and selfish genetics want our worm heroes to spread their seed as widely as possible.
Unfortunately, the dry ground limits their travel because the dry surface would kill them. They only get to do the very horizontal tango with that next-door neighbor (again) … except when it rains. In the rain, the intrepid worms use the wet ground and puddles to take a daring dash to get as far away from home as they can. They leave the safety of their hole in the ground because this is their chance to find a new worm to mate with.
Next time you see a stampede of worms, you will know why. Spread the word. Those little monsters crawl across the dangerous pavement after it rains because they are looking for love.