Yes, worms do have brains – however, their brain is perhaps not in the form we might first imagine. The brains of worms do not exist in the cerebral sense we might usually think of.
In plain terms, this means the worm brain is located directly alongside the other vital organs. Nerve endings located at the skin connect to muscles that are controlled by the brain, for example.
The brains of worms are not as complex as those of other animals, as you might expect. There are similarities between worm brains and those of lobsters and snails.
They, too, have nervous systems which are far simpler than those of more complex animals.
How many brains do worms have?
Worms are in the category known as ‘annelids’. Most annelids have two cerebral ganglia, which are the brainpower engines controlling their bodies.
Because of this, some people feel it is appropriate to say earthworms have two brains!
Do worms have two brains?
Technically, yes, worms have two brains. Annelids, like earthworms, have two ‘cerebral ganglia’ which are connected to other areas of their body.
Via ‘motor nerve’ fibers and ‘sensory’ fibers, these bundles of nerves send signals to activate movements and other functions of the body.
The central nervous system of a worm is much like yours and mine, in that it’ll still support the worm’s circulatory system with blood flow, and will support body segments such as the head region.
This goes for an earthworm’s body, the pork tapeworm, and in fact any other type of worm you can think of.
Many of us have witnessed how worms often react to various stimulation.
On the ground surface, we can watch them avoid obstacles, (people often wonder whether worms have eyes) sensing a better route towards or away from a rock or water.
When worms are touched, they wriggle and sometimes swing around. This is a direct response to sensory cells’ perception.
They also respond to ‘chemoreceptors’ on their skin. These enable them to discover chemicals in the soil which they will determine to be acceptable or undesirable.
It can be observed how earthworms move away from material they are repulsed by. We can also see them engage their muscles to move towards and work their way through suitable food.
Brainpower and survival
Aside from responding to cooling temperatures and searching for more agreeable conditions, worms seek food. Being relatively strong, a worms mouth can grind up a variety of materials.
Despite having no teeth, they munch away on tough organic material as well as softer options. Worms swallow pieces of dead cells from decaying leaves, organic food scraps, etc.
As the food passes through the worm’s stomach, it becomes worm the much-appreciated castings (i.e. worm poop).
This is just one of many processes a worm goes through – as you can imagine, a worm’s going to need a brain for the same purpose as you or I – to keep pumping blood forward, to expel carbon dioxide, and to help undigested organic matter pass through.
Their brains are connected to their nerve cells, skin, and muscles throughout the entirety of the worm’s body length.
Much like the human brain, it is thanks to the worm’s brain that the worms:
- breathe air
- regulates their body temperature
- can detect light using their light receptors
- makes the worms hearts pump
- can detect animals moving nearby
- and are able to use their circular and longitudinal muscles, as the body moves forward.
The nerve cords and nerves extend all across the body segment and head segment of the worm, meaning that while they may not have so many body parts as you and I, the adult worm can still control its own bits and pieces freely.
Do worms feel pain?
In 1979, the New York Times published an article about the work of Swedish research into earthworms brains having connections to immunoreactive nerves.
This led the researchers to conclude that worms do, in fact, feel pain.
Evidence in experiments proved that worms have evolved to protect themselves from pain by producing a chemical reaction in a similar way to humans.
That is, they produce ‘beta endorphins’ and ‘enkephalins’.
These react in much the same way opiates do in humans. That is, to assist them to endure pain.
It has been noted that worms do feel pain when they are impaled on hooks for fishing.
It has been further noted that their nervous system is simple and not complex. This means that worms are incapable of processing emotional data.
Therefore leading some to believe that whilst feeling pain, they are not experiencing suffering.
Summary
Yes – there are more than just a few wormy muscles beneath that wriggly exterior, and a worm certainly has a brain.
In fact, it pretty much has two – and while this might sound a bit complex, a worm’s nervous system is much more simple than yours or mine – as you might expect!
