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Why Do Earthworms Come Out at Night?

Why Do Earthworms Come Out At Night?

If you have a garden in your yard, compost pile, or like to work with soil, you must be very familiar with the shiny earthworm.

Even though they are not the most beautiful invertebrates, they are essential to the overall health of your soil. They can aerate the soil, provide plants with more accessibility to nutrients, and even fertilize the substrate.

Even though people like to say “earthworm” to the familiar picture of the worm that likes to dig soil, there are about 6000 varieties of these invertebrates.

You can find 180 species in the US alone. And something you may have seen before is the “nightcrawler” variety who likes to come out at night and feed.

But have you ever wondered why earthworms like to come out at night? Continue reading to find out!


Earthworms are essential creatures to keep your lawn and garden healthy. They help aerate the soil, make nutrients, and fertilize the soil. But have you ever wondered why these invertebrates come out at night?

Well, it’s because of the following reasons:

  • To avoid the harsh sun.
  • To preserve their moisture.
  • To avoid predators.

But earthworms do come out during the day when it rains. And scientists still don’t know why they do this!

If you don’t know why earthworms like to come out at night, the reasons below should make you understand.

3 Reasons Why Earthworms Like To Come Out at Night

Reasons Why Earthworms Like To Come Out At Night

As you may know, earthworms don’t have eyes because eyesight is useless when you live underground.

But they have photoreceptors in their body that can detect light, which helps them distinguish if it’s already dark outside.

So, why come out at night?

1. Avoid the Harsh Sun

Avoid The Harsh Sun

Earthworms are invertebrates that can die when exposed to sunlight and warmth.

Their survival depends on how well they can moisturize themselves.

So, if they come out in the daytime, they can easily dry out because of the sun.

2. Preserve Moisture

Preserve Moisture

Earthworms don’t have lungs. But they instead breathe into their skin, which has to stay moist to ensure oxygen exchange continues. That is why they prefer moist soil.

It’s risky for them to come out of their burrows since there is a high chance of drying out on the surface.

3. Avoid Predators

Avoid Predators

There are plenty of predators in the daytime, like birds who can make an easy meal out of earthworms. But at night, they can camouflage themselves and hide in the darkness to eat.

So, it would be best for them to come out of the night because they’ll become easy pickings during the day.

Because of such threats, earthworms will only come out at night to feed on detritus material like grasses in the vicinity.

Nightcrawlers are the typical worms that come out at night when the grass is wet with dew, making it easier for them to feed on it.

These worms are larger than your typical earthworms and greyish in color. So it’s not difficult to recognize them. You can easily spot them when your lawn is cut short. Or the grass is scarce.

Why Do I See Earthworms During the Daytime?

Why Do I See Earthworms During The Daytime?

You may see earthworms in the daytime when the sun has not fully risen. And the soil is moist from dew. But they’ll quickly burrow back down after a short time.

That is why you hear the saying, “the early bird catches the worm.” But besides dawn, earthworms also like to come out when it rains.

There are many hypotheses why earthworms like to come out during the rain.

One popular one that people spread is that the worms go out the surface to avoid drowning. But this has been disputed by many experts. As was said, earthworms don’t have lungs. So it’s difficult for them to drown. But they could be coming out because of poor oxygen.

Another popular explanation is that earthworms think raindrops sound like moles or predators. Moles make vibrations when they move underground. And earthworms could mistake the vibrations of raindrops as moles hunting. But this theory has never been tested by experts.

The best explanation that experts have for this behavior is earthworms may want to cover new territory or find mates. They escape the harsh sun’s heat when it rains. And moisture is not an issue.

But they become more susceptible to predation and can get trapped on sidewalks and roads.

There will be new research and revelation in the future. But for now, this is what experts have to offer as an explanation.


Earthworms are essential animals to the environment. They help aerate and fertilize the soil and make nutrients more accessible to plants.

But if you want to know why earthworms come out at night, it’s because it is safer. They can avoid the harsh sun and the detection of predators.

However, there are times when earthworms come out in day time when it’s raining.

There’s still no specific reason why earthworms do these behaviors. And more studies will be done by experts in the future.

Frequently Asked Questions

What Do Earthworms Eat?

Earthworms eat a variety of matter. And most like to describe them as omnivores because they eat plant and animal matter. But they best describe as detritivores because their diet is decaying organic matter.

How Big Can Earthworms Get?

That depends on the species:

The giant Gippsland earthworm in Australia is the largest known earthworm in the world. Even though it’s only 2 cm wide, it can grow up to 3 meters long.

In North America, you have the giant Palouse earthworm, which can grow up to 1 meter long.

Both species are threatened due to human activity.

How Do Earthworms Reproduce?

Earthworms are hermaphrodites, meaning they have both sexual reproductive organs. This means you can put any earthworm together. And they can reproduce whenever they want to.

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