Why Do Worms Come Out in the Rain?
The term worm was originally used to define any non-arthropod invertebrate animal. Today, it is used to describe animals with a long body, no legs, and invertebrates. There are many different types of worms, and you can find them throughout the world. However, usually the term worm is applied to “earthworms.” Let’s examine the earthworm!
There is actually more than one theory to answer why do worms come out in the rain. One theory states that earthworms may come out after heavy rainstorms because the water floods the soil. Earthworms travel underneath the soil because the soil provides a moist environment for their skin.
However, when if it rains heavily, the soil floods and the earthworms have difficulty breathing. Scientists theorize that they travel to the surface of the soil to ensure that they don’t drown. If they cannot escape to the surface due to rocks or other blockages, the earthworms may die. Sometimes earthworms get trapped when they travel to the surface of the soil.
Another theory is that earthworms emerge from the soil after it rains because they are trying to mate with each other. This theory is not as well received by the scientific community, but there are a small number of followers that believe earthworms come to the surface after a storm to mate with other earthworms.
More scientists believe that the moisture on top of the soil after it rains provides a slicker environment for earthworms to travel on. Under this theory, earthworms come to the surface because they want to travel quicker. Furthermore, the humidity of the surface is higher after a thunderstorm, and thus earthworms can travel on top of the surface for longer periods of time without getting dehydrated as quickly.
A final theory is that the earthworms come to the soil after a rainstorm due to the presence of other organisms underground. When soil increases in water content, organisms increase their respiration. When organisms increase their respiration, the soil may increase in the presence of carbonic acid. This is because when the organisms increase their respiration, there is an increase of carbon dioxide gas underground. This carbon dioxide gas then dissolves in the water, increasing the presence of carbonic acid. The earthworms, in an attempt to escape the overly acidic soil, travel to the surface of the soil.
How Are Earthworms Classified
Earthworms are members of Oligochaeta, and are in the phylum Annelida. Previously, they were located in the order Opisthopora. Some classical systems place them in the suborder of Lumbricina, or alternatively in the order Haplotaxida. However, these latter classifications are debatable.
Anatomy of an Earthworm
An earthworm has a tubular body, which contains a digestive system. The outside of its body is covered with a slimy and wet exterior. The outside body also has several indentations on the outer body, which are known as “chaete” or “setae.” Earthworms are typically a brownish or reddish color, although some earthworms are black in color.
Earthworms are usually approximately eight to ten inches long, and there are currently over two thousand and four hundred different species of earthworms. Some earthworms may grow up to twelve feet in length, while other earthworms may be as short as an inch.
Earthworms have two central blood vessels that are extended throughout their body. One of the vessels is a dorsal blood vessel, which circulates blood through the anterior end of an earthworm. The other vessel is a ventral blood vessel which pumps blood to the posterior end of an earthworm. The former blood vessel is contractile, and the latter blood vessel receives the pumped blood from the dorsal vessel.