In this article we will try to answer the question of why earthworms come to the surface of the earth after it rains.

Many people may not know, but an ordinary earthworm plays an extremely important role in nature, transforming large fragments of various substances into substances that make the soil fertile. They carry out this necessary function by pushing substances deep into the soil.

Worms can often be seen on the earthen surface after the rain has passed. Having got out, they arch their bodies, as if they were enjoying the water. Almost all experts believe that the following factors influence this behavior of worms after the rain has passed:

• temperature;
• pH balance;
• innate instinct.

Main version

But the majority is inclined to a simple opinion why worms get to the surface, namely, raincoats crawl to the surface simply so as not to drown in the swampy ground.

Scientists who studied more than eighteen species of worms came to a similar conclusion. They believe that worms crawl out due to the specifics of their own respiratory system because oxygen enters their body through the skin. To absorb air, the body of the worm must be wet, in particular, as a result of this, they are covered with specific mucus and so that it does not dry out, they live only in moist soil, but if the humidity is too high, they begin to suffocate, since their body ceases to receive oxygen.

Simply put, raincoats are pulled out of the ground after rainfall so as not to drown in the marshy ground.

It is noticed that different types Worms need oxygen in varying amounts. Likewise, its absorption depends on the time of day. Several species of worms have been studied. Representatives of the same species when it's raining, are selected to the surface, while others are not. It was found that one species requires much more oxygen than another, and its absorption depends on the time of day.

This means that waterlogging of areas can become a dangerous problem for raincoats, because due to high humidity they will suffocate, however, they will not be able to live on dry soils. In addition, crawling out of the ground is dangerous for worms because they can simply be pecked by birds. Worms underground can only be safe unless you consider that an animal like a mole likes to feast on them.

A few more versions

A likely reason for worms crawling out after the rain has passed may be the change in soil temperature that they sense during the rains. The bulk of raincoats live quite deep in the ground, because there the temperature is most suitable for them.

Another version of why a worm is chosen after rain is that after the rain passes, the acidity of the soil changes. Other experts, in turn, believe that certain types of soil are prone to receiving increased concentrations of cadmium after rain has passed.

Another explanation for why the earthworm crawls out after the rain has passed is that certain species cannot long time be in the water.

Another explanation could be that certain worms do not require much air, while water saturates the soil with oxygen. But there are also types of worms that do not drown in water, but on the contrary feel great in it.

Another explanation could be that this is their natural behavior. They probably come to the surface because the majority of them are simply accustomed to doing so, and not because there is too much oxygen in the soil.

According to another explanation, worms crawl to the surface because they are simply partial to moisture. They like to crawl out of the ground to enjoy the moisture on the earthen surface.

Video “When and how to collect crawlings”

This video shows how to collect an earthworm after a rainstorm.

This article presents the most common and proven hypotheses. The opinions of experts and their assumptions are given. The article contains Interesting Facts. The article tries to give an objective answer to the question. Earthworms, or as they are also called earthworms, are worms that live in the ground. Their name is determined by the fact that they tend to the surface after rains. Their length averages from three to fifteen centimeters. But it can also be up to forty centimeters. And sometimes the worms are longer (up to two meters). More than a thousand species of all kinds of worms are known. Basically, worms live in the tropics. Worms feed on organic matter that decomposes.

Since childhood, everyone has noticed the fact that worms crawl out. This is what happens and has always happened. This fact will amuse many. What is the reason for this behavior? These questions are asked by many people, as well as professional scientists and researchers of the phenomenon. The reasons for this behavior are not known. But the fact still exists.

Reasons for worms coming to the surface

Earthworms crawling to the surface is a familiar sight for people since childhood. This especially happens after the recent heavy rain. There are the most different opinions and guesses. The worms are probably worried about their well-being. Every curious person or adult racks their brains. At school, biology courses do not always cover all issues. But a school biology teacher cannot always answer students’ questions and explain the principle of worm behavior.

As such, there is still no unambiguous scientific answer. Previously it was believed that worms crawl out because they can drown in water. Then this hypothesis was refuted, since worms breathe through their skin. According to experts, worms are able to survive for a certain period of time (up to several days). But there are a number of assumptions that are put forward by scientists from time to time. Here are some of these hypotheses:

First guess is that the soil temperature changes. Worms feel this strongly. When it rains, the temperature changes by several degrees. At the depths of the earth where worms live, the temperature is comfortable for their existence.

Second guess consists of changing the acid-base balance. After precipitation falls, the soil becomes more acidic. This forces the worms to come to the surface so as not to die in changing conditions. Increased cadmium concentrations may also have an effect.

Third guess in changes weather conditions. There are worms that cannot exist in water and die accordingly.

Fourth guess consists of a lack of oxygen.

There is one more point that interests observers. Why do worms get onto asphalt? Is it a footpath or something else solid. Worms gravitate towards something solid because there is less moisture there. Asphalt or concrete, from which paths are made, get less wet. If you look closely after the rain, you can see how the worms move from the ground to the asphalt.

Which countries are participating in the study and have achieved success.
Listed above are the main hypotheses put forward by experts different countries. There are some more thoughts. This may be the so-called herd instinct. Zoologists have different points of view on this issue. There are different approaches to studying.

English and scientific zoologists achieved major successes in the field of research. Various specialists adhere to different study methods and scientific approaches. These experts are of the opinion that worms need oxygen. And from time to time, they take advantage of the opportunity to choose.

Everyone knows that a worm breathes through the skin. The worm has gills, but they are not so developed. Worm burrows are usually about eighty centimeters long. In large individuals they can reach up to several meters. When rainwater gets into the hole, the worm suffocates and crawls not down, but up (trying to escape and not die).

On the surface, those who were able to crawl out of the puddle remain alive, and the rest (who could not) simply die. Because oxygen is better absorbed through the surface of the skin under these conditions. There is also an opinion that worms mistake the sound of rain for the approach of a mole. The mole is the most important enemy for worms and poses a danger to them. The raindrops that fall resemble the sounds of the approach of this predator. This creates an atmosphere of certain danger for the worms. They are trying to escape as best they can.

There are many opinions and discussions here. All everyday ideas develop historically and are passed on from generation to generation. Some even argue on this topic. Some people think that worms want more moisture (). The soil in which worms live does not retain moisture. And asphalt does not absorb moisture.

This explains the desire of the worms. After heavy rain, you can see the movement of worms. Some of them die under the wheels of a car or under the feet of passers-by. Perhaps this version has some meaning. But someone says that they should have enough moisture (since it rains in winter and in summer and in the off-season). The phenomenon occurs especially after heavy rain.

Why do worms crawl to the surface? The people give their answer. Folk sign, many people say that this happens before the rain. This opinion is especially shared by villagers who are accustomed to following nature. And you can definitely trust them. We can say that there is no unambiguous explanation for the phenomenon. There are opinions. Some of them provide more insight, others less. At the same time, research by specialists continues and perhaps the answer will be found. And everyone will know why worms crawl to the surface.

Is it true that earthworms love rain?

No, that's not true. Indeed, when it rains, worms crawl out of the ground, but of course this does not happen because they love it. Rainwater displaces air from voids in the soil. As a result, due to lack of oxygen, the worms crawl out. And the harder it rains outside, the more earthworms you can see crawling on the surface of the earth.

And from here follows the answer to another popular question - can an earthworm live in water? No, he can not. Earthworms, like humans and all animals oxygen is needed for breathing, only fish and some mammals that have adapted to being under water for a long time, such as dolphins or sharks, can live in water. Amphibians - commonly known as frogs, are distinguished here as a separate form; being born in water, they then lose their gills, and with them the ability to live only in water, although they retain a partial ability to breathe under water through their skin.

Yes, this is true, but this is why it becomes clear if you carefully study the composition of the ash.

There are three main components in ash: phosphorus, potassium and calcium. The first two fertilizers are very useful, and the last one is calcium; we commonly call this element lime. And it can be up to 80% in the ash, on average 27-30%. As you probably remember from school, and many from your own practice, our body gets burned when it comes into contact with lime. We won’t go into the essence of the chemical reactions, just imagine, the surface of the earthworm’s body is approximately similar in sensitivity to the surface of our intestines, imagine what will happen to the worm if it gets into the ash - why would it love it, would it remain alive.

Year after year, after rain, we can constantly observe the appearance of many hundreds of earthworms on the soil surface. For many of us, this fact may cause disgust; for others, indifference. However, few people think about why worms crawl out after rain?

Causes of worms

There is still no scientific explanation for this fact, there are only assumptions. Let's give several versions.

1. Change in soil temperature. Worms are very sensitive to this. During rain, the soil temperature drops by several degrees at once. After all, deep underground, where these creatures live, a fairly comfortable and warm temperature for their livelihoods.
2. A change in the acid-base balance is the second reason. The soil becomes more acidic after precipitation. This fact encourages them to appear on the surface in order to avoid mass death. In addition, during rain, cadmium concentrations are observed in some soils. This can also affect the behavior of earthworms.
3. Phenotypic variability of nature, that is, inconstancy. Individuals of this type of worm appear that may die while for a long time in water.
4. The next reason why earthworms crawl out is a lack of air, and water enriches the top soil layer with them.
5. Another version of this animal behavior may be the “herd instinct,” when worms appear on the surface, following their relatives.
6. But still, the simplest reason is the relationship of worms to moisture, why they were called earthworms. Zoologists believe that they appear on the surface of the earth to enjoy the water. This behavior in rainy weather is also typical of other animals, such as isopods.

Many of us have seen earthworms crawl en masse to the surface of the earth during rain, but few know why they do this. However, scientists have many interesting hypotheses on this matter. Some believe that the worms are driven to the surface by the desire to travel, while others believe that the reason for this behavior is the fear of moles. There are those who consider both of these hypotheses to be fair.

There are many traditional explanations for this behavior of earthworms (suborder Lumbricina), however, they are all very, very doubtful. People far from zoology believe that worms come to the surface during rain because they love water very much and try to take advantage of the situation in order to increase the humidity inside their body. However, this version is very far from reality - after all, the humidity in the soil itself after the start of a rainstorm grows quite quickly and it is enough for the worm to simply migrate from the lower layer to the “soaked” upper layer. But crawling to the surface, where it can become easy prey for predators (which in bad weather do not sleep), this creature has absolutely no need.

Biologists explain this phenomenon as follows: during rain, water penetrating into the soil floods the tunnels through which earthworms move. That is, these animals do not run towards the water, but from it - they are simply afraid of drowning. Until recently, this hypothesis was considered the closest to the truth, although it still had one weak point. The fact is that, according to research by physiologists, water is not as dangerous for worms as we think.

To begin with, these creatures generally feel more comfortable in conditions of high humidity, since they breathe through the surface of the body, and the more damp it is around, the better oxygen passes into their body. In addition, experiments have shown that earthworms can generally live for several days in a jar of water and feel no worse than in the soil (interestingly, almost every angler knows about this). Thus, they can calmly wait out the rain even in completely flooded “apartments” and not endanger their lives by crawling to the surface.

However, why do worms do this? Zoologist Christopher Lowe from the University of Central Lancashire (UK) believes that they use the rain to make long journeys. He calculated how much energy these creatures spend crawling a distance of one meter along the surface of the earth and in the soil. It turned out that crawling on the ground was more profitable - the energy was consumed five times less than when the worm squeezed between soil lumps. Well, since earthworms do not like dry air, they prefer to settle in damp weather.

However, Professor Joseph Gorris from the University of Vermont (USA) does not agree with the conclusions of his colleague. In his opinion, this behavior of worms is forced, but it is not water that forces them to crawl to the surface, but... fear of moles! The zoologist believes that these creatures perceive the sound of rain as the approach of an underground predator, which is their enemy (contrary to what is written about the mole in fairy tales, this animal is not a vegetarian at all, but an exceptional meat eater, and it is worms that are the basis of its diet).

Using the latest acoustic equipment, the professor found that drops falling on the surface of the earth and a mole moving underground produce very similar vibrations. It is possible that it is this similarity that deceives the worm, which is not able to determine where the source of the sound is (its hearing aid, alas, is imperfect). As a result, the animal gets scared and rushes upward - although it is also dangerous there, the fear of the mole turns out to be stronger.

In order to test their assumption, Professor Gorris and his colleagues conducted an experiment, which, again, is known to all fishing enthusiasts. They stuck a stick into the completely dry ground, put an iron sheet on top of it and began to shake it. The leaf immediately began to vibrate (and, according to instrument readings, this vibration was similar to that which causes raindrops to fall to the ground), and the vibrations were transmitted through the rod to the soil. And what do you think - literally a couple of minutes after the start of the experiment, worms crawled out of the ground, although there was no trace of rain!

So, it is quite possible that it is mole phobia that drives earthworms to the surface of the earth. However, some zoologists believe that both Dr Low and Professor Gorris may be right. It is possible that the worms initially crawl out of fear of moles, and then, having understood the situation, they decide to move to a more safe places. It is also quite possible that in the clusters of these animals formed on the surface of the earth, social and even mating communications take place - partners find each other and mating occurs (since earthworms are hermaphrodites, there are no gentlemen or ladies among them, the animals simply exchange sperm with each other) .