Do Worms Feel Pain? (Can Earthworms Sense Painful Stimuli?)

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Worms can actually feel all kinds of things. For example, it is known that worms react to various types of stimulation. These include sensitivity to light, extreme temperatures and moisture.

Via their nervous system, the brain controls the active response of their body. This may be burrowing deeper to escape ultraviolet light, or seeker a cooler space. But can worms experience pain, for example, will a worm on a fishhook feel pain when used as fish bait?

Yes, worms can feel pain. However, it is not in the same way humans do. Their bilobal brains, of course, are simpler than the far more complex brains of other animals higher up the food chain. Whilst their brains respond to various stimuli transmitted via their nervous system they do not react emotionally to pain.

Let’s dig a little deeper.

Does It Hurt a Worm to Be Cut in Half?

Yes, it is now accepted that worms feel pain – and that includes when they are cut in half.

They do not anticipate pain or feel pain as an emotional response, however. They simply move in response to pain as a reflex response.

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They may curl up or move away, for example, from painful or negative stimuli.

When cut in half, both parts may move. However, only the part containing the head has a chance of surviving. Read and know more if worms regenerate or not.

Despite the worm’s very simple nervous system, never cut a worm in half – it’s never good for their well being and worms squirming aren’t doing it because they’re having fun!

Do Hooked Worms Feel Pain?

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Not always – and there is a very interesting study behind this confirmation.

Over ten years ago, the Norwegian government called for a scientific study to test whether or not invertebrates feel pain. Invertebrates cover a wide spectrum of animals including crabs and worms.

The study needed to take place in order to cover all aspects of Norway’s animal protection law – do worms actually feel pain when we use them for fishing, for example?

The study, led by Professor Wenche Farstad, concluded that most invertebrates feel no pain due to their very simple nervous systems.

He stated that crabs cooked in boiling water, just like live worms used as fish bait, did not feel pain and therefore people should feel no particular responsibility for their physical reactions to the boiling water nor the worms squirming.

They concluded that red wigglers only display reflex curling on the fishhook – and to an extent feel a natural physical reaction to the object impaling them – but due to their very simple nervous system, they cannot have felt pain.

The same rule, they argued, applies for crabs boiled alive.

However, it is important to remember that this is simply a scientific opinion.

In truth we may never truly know whether earthworms feel pain or not – however, some suggest that humans are right to feel bad about causing any animal suffering and that since the common earthworm is an animal, just like any other live worms, they deserve respect and care.

The Norwegian study is interesting as it appears to rally against some of what we know about the damage that people can inflict on animals.

However, research is still ongoing with regard to how invertebrates respond to pain, whether unlike mammals or not.

Do Worms Feel Love?

The answer seems to be ‘yes’ – to an extent. Believe it or not, there is also a study to back this up.

In September 2017, researchers from three establishments agreed that yes, worms display social behaviour and do indeed express love. The word ‘feel’, however, implies a conscious emotional response.

At the University of Southampton, Porton Down and at Belgium’s KU Leuven, researchers established that worms display a parental form of love.

Experiments conducted on the small, one-millimetre long C-Elegans worm revolutionised their thinking! 

The worms studied displayed a pre-programmed sense of caring for their offspring. Researchers discovered the worms deliberately chose to lay their eggs in the same space as their food source.

This means that once hatched, offspring would share and eventually compete for food in the same dining area.

Furthermore, the adult worm parents exhibited an intuitive reserving of some of the available food, instead of devouring it themselves. In other words, they appeared to be saving some food to share.

The scientists also revealed another significant and major discovery. It has long been known that in humans, a hormone called Oxytocin influences social behaviour. It is sometimes referred to as the ‘love hormone’.

In the worms studied, an equivalent nematode hormone was discovered. It is called ‘Nematocide’ – it functions in much the same way as the human hormone.

Therefore, the ‘loving’  behaviour of the worms was attributed, at least in part, to Nematocide.

Despite the absence of a complex brain with the capacity to display emotions, worm brains display ‘caring’ activities. It appears that these behavioural patterns are prompted by the release of hormones.

The studies suggest that worm parents also showed love by carefully choosing where to store their eggs. This is something that appears to have taken genuine effort, and at least some form of innate care response.

To know further more about whether worms have feelings/emotions or not, read our other related articles.

do not cut worms into half

Final Thoughts and Summary

The significance of all this research is very important. Worms may be simple creatures, but research into how they react and behave show us that, to some degree, we all share similar traits.

The experiments have also changed some of our perceptions in relation to the pain these creatures feel. Whereas it was considered worms did not feel pain, we now know that they do.

Worms may not feel emotionally stressed by pain, but what we do now know that injuring them, cutting them or hooking them likely hurts – and we can imagine.

This has led to many people moving away from live bait when fishing, and towards more careful worm conservation in the garden.

A worm’s brain may only be small, but despite the scientific study funded in Norway, it is a fair assumption that they will display more than only reflex curling if they are inflicted badly enough.

The final point to take away is, therefore, if you can, avoid hurting worms – they haven’t done a thing to deserve it.