Here’s “How Earthworms Feel Pain” (Nervous System Explained)



Written by Katie Piercy

Earthworms do feel pain, as they have a nervous system that allows them to detect when they have been injured. They do not appear to feel emotional pain, however, in the same way that we might.


Earthworm’s nervous system explained


For many centuries, many people believed that animals did not experience pain or have emotions. Today, scientific studies have shown us that most animals do experience pain, and many have some kind of emotional senses.

It can be difficult to assess when animals feel pain, as most animals mask when they are in pain or injured, as this will make them a target for predators, or could cause them to be excluded by their peers.

If we observe an earthworm’s behaviour, we can see that they react strongly if something occurs that may cause them pain. For example, if an earthworm gets salt on its skin, or if it is cut in half, it will wriggle fiercely, as if trying to escape.

Nervous System ComponentDescription
GangliaClusters of nerve cell bodies, serve as “mini-brains”
Nerve CordLong cord running along the length of the body
NervesBundles of nerve fibers extending from the nerve cord
Sensory ReceptorsSpecialized cells for detecting stimuli and transmitting signals
Ventral Nerve CordMain nerve cord on the underside of the worm
Table 1: Earthworm Nervous System Components

Beyond such observations, we know that earthworms do have a nervous system, that like ours relays important sensory information to its brain. The earthworm has a number of different sensors that can detect a range of external stimulation.

Earthworms have sensors that can detect touch, heat, light and various chemical compounds. If an earthworm nears something that its sensors suspect might be harmful, the feedback from its sensors tells it to move away from the potentially damaging situation.

earthworms eyes

For example, earthworms tend to be sensitive to light, and therefore they will draw back if they emerge at the surface during daylight. Certain vibrations also tell them they may be near a mole, meaning they will aim to move away from where they think the mole might be.

Sensory OrganDescription
Epidermal ReceptorsSensory cells in the body wall for touch and vibration
PhotoreceptorsLight-sensitive cells for detecting changes in light
ChemoreceptorsCells for detecting chemical substances in the environment
MechanoreceptorsCells for detecting mechanical stimuli, such as pressure or movement
Table 2: Earthworm Sensory Organs

All this tells us that earthworms try to keep clear of harm. This makes perfect sense, as they would not survive to have offspring if they happily wandered into a harmful situation.

What we can’t be sure of is whether earthworms feel emotional pain. Emotional pain adds significantly to the negative impact of pain, both mentally and physically. Currently, it is thought that the earthworm’s brain is not complex enough for it to experience emotional pain.

Also read: Earthworms Reproduction Explained (Sexual and Asexual)

Do earthworms die if cut in half?

While no earthworm is going to enjoy being cut in half, the good news is that earthworms can sometimes survive being cut in half. If the head of the earthworm is intact, and the cut is below the saddle, then this half of the earthworm can regrow its body and survive.

Sadly, however, the other half of the worm will not survive, slowly shrivelling away. Yet, even though the worm can potentially survive this, it is clear that they do not enjoy the process, and will feel pain from it. Therefore, it would be considered cruel to purposefully cut a worm in half.

Also read: Earthworms Closed Circulatory System Explained


Katie Piercy

Katie Piercy, a conservation industry veteran with a diverse career, has worked in various environments and with different animals for over a decade. In the UK, she reared and released corncrake chicks, chased hen harriers, and restored peatland. She has also gained international experience, counting macaws in Peru, surveying freshwater springs in Germany, and raising kiwi chicks in New Zealand.

Meadows have always captivated her, and she has often provided advice and assistance in managing these habitats. From surveying snake's head fritillary in Wiltshire to monitoring butterfly species in Norfolk, Katie's dedication extends even to her own front garden, where she has created a mini meadow to support wild bees and other pollinators.

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