How come earthworm can still live after splitting in half?

Earthworms have what is referred to as a “ladder-like” nervous system.

Earthworms are disliked by a large number of humans, and birds like eating them since when it rains, they will often abandon their underground habitat. The common earthworm is known in Latin by the name Lumbricus terrestris. These animals have strange characteristics that many people witnessed as children: You can slice through the worm with a pointed shovel, but both ends of the earthworm’s body will continue to move around. The worm has the ability to recreate the lost part of its body entirely. But how does this even happen in the first place?

The location of the cut matters

How come earthworm can still live after splitting in half?
(Credit: Addison Wesley Longman)

Even though it is missing a significant portion of its body, the worm is nonetheless able to live on. The earthworm has the ability to regenerate the lost section of its body. However, it seems to make a difference where on the worm the cut was made. Only the front portion that contains the mouthparts can be regenerated, and this can only happen if only a few segments are lost. The head of the worm is where the digestive system and the central brain are found.

Surviving without a head

Yet, it is still possible to encounter surviving rear ends that do not have a head. Due to the fact that a worm without its head is unable to eat effectively, it can only have a short lifespan in this scenario. This rare phenomenon happens as a result of both ends being genuinely capable of regeneration. However, the rear end can only give birth to another rear end; hence, all of the vital organs that are located in the front section are lost. The front end, on the other hand, has the capability of regenerating a new rear end and creating a whole worm in this way.

Still, there is a low chance that these damaged worms will be able to live in the wild because of infections in their wounds.

How does an earthworm regenerate its missing part?

It is known that approximately a week is required for the worm to develop its missing body section. During this period of time, a wound layer will begin to develop on the end. Cells from the gut and the skin move into the damaged area to begin the process of progressively forming the new body segments. The segments on the rear end regenerate quicker than those on the front. Additionally, the rear replacements are narrower, at least at the beginning of the regeneration. It takes about two to three months for the pigmentation of new segments to return to the worm’s true color.

How earthworm still moves after being cut off

The separated ends of an earthworm’s body may appear to crawl around so deftly. This phenomenon has a biological cause as well: Earthworms have what is referred to as a “ladder-like” nervous system, which, as the name implies, goes through the whole body similar to a rope ladder. The pain causes the earthworm’s flight instinct to be activated, and it does so whether the worm is only squeezed or entirely cut. This response causes muscular twitching, which is why the earthworm appears to crawl around after being cut. However, if the shovel strikes the earthworm in the wrong spot, the animal may not regenerate from it.

By Bertie Atkinson

Bertie Atkinson is a history writer at Malevus. He writes about diverse subjects in history, from ancient civilizations to world wars. In his free time, he enjoys reading, watching Netflix, and playing chess.