Yes, worms can feel touch, vibrations, light, temperature, and chemicals through highly sensitive receptors in their skin, allowing them to navigate, find food, and avoid danger, but their reaction to stimuli is a protective, mechanical response rather than complex pain as understood in humans, though research suggests they have mechanisms to avoid harmful stimuli.
But a team of Swedish researchers has uncovered evidence that worms do indeed feel pain, and that worms have developed a chemical system similar to that of human beings to protect themselves from it.
Worm's main sense organ is it's skin. It does not have eyes and ears. However, it's skin is very sensitive to touch, light, temperature and moisture.
Like us, worms move, eat, sleep, taste, smell and can sense touch. Although they have only 302 neurons (compared with our 100 billion), they are surprisingly clever.
Good Worms
Most worms you'll encounter won't pose any threat to you or your pets. These include earthworms, redworms, nightcrawlers and more.
If just a little bit of a worm is broken off, it can grow a new head or tail. But if you cut a worm in half, it will not live. Worms have 5 hearts located close to their head. If a worm doesn't have all five, blood cannot get to rest of their body.
Haemoglobin contains iron, which means most worm blood – including that of earthworms and leeches – is red.
They're covered in small bristles, called setae, which help the worm wiggle and burrow into the soil. Earthworms do not have eyes. They spend most of their time underground and don't need to see. But they can sense differences in the light.
This consistency in behavior across different forms of stimuli supports the idea that worms may indeed experience a sensation of stimuli they want to avoid, although the experience is more primitive than the emotional or physical pain felt by humans or other mammals.
Do worms have hearts? Worms possess a heart-like structure called an aortic arch. Five of these arches pump blood around the worm's body.
Needless to say, Darwin would have been the first to admit that worms' thoughts are probably quite modest. But that they think at all was enough to validate his theory of evolution – and to demonstrate beyond a doubt that all living things share similar cognitive processes.
However, before they die the female worms lay tiny eggs around the anus. This tends to be at night when you are warm and still in bed. The eggs are too small to see, but cause an itch around the anus. You then scratch around the anus to relieve the itch.
An earthworm's lifespan depends on its environment. Those with a wholesome country lifestyle can live up to eight years, but those in city gardens generally last 1-2 years. They often die from changes in the soil (drying or flooding), disease or predators such as birds, snakes, small animals and large insects.
Moreover, some vertebrates, such as fish, may lack the neural machinery or architecture to consciously experience (i.e., to feel) noxious stimuli as painful (Key, 2015a).
Norway might have considered banning the use of live worms as fish bait if the study had found they felt pain, but Farstad said "It seems to be only reflex curling when put on the hook ... They might sense something, but it is not painful and does not compromise their well-being."
They don't have the neural capacity to understand the concept of location. Worms have no idea where they are, where they are going, or even that they're moving at all. They sense and respond by reflex. They bend in response to higher concentrations of chemicals.
Worm infection symptoms vary but commonly include an itchy bottom (especially at night for threadworms), abdominal pain, diarrhea, bloating, gas, nausea, fatigue, and changes in appetite, with some infections causing no symptoms at all. More severe or persistent issues can involve weight loss, vomiting, skin rashes, or even muscle/joint pain, requiring medical diagnosis for confirmation and treatment, as these signs overlap with other conditions.
If an annelid is cut in two, they can regenerate to some degree, and in some species you can even end up with two worms. The common earthworm, however, will only regenerate from the tail end; the head end always dies.
Don't be fooled though, they make up for it with the interesting aspects they do have. Like five hearts that squeeze two blood vessels to push blood throughout their little bodies. Earthworms have mucus and little hairs covering their skin that allows them to move through different types of soil.
Most earthworm species have five aortic arches or 'hearts' that move blood around the body.
What animal has purple blood? Peanut worms, which are a kind of marine worm, have purple blood. This is due to the presence of hemerythrin, an oxygen-binding protein.
In contrast to a popular urban legend, erythorbate is NOT made from earthworms, though the U.S. Department of Agriculture reports receiving many inquiries about erythorbate's source. It is speculated that the similarity in the spelling of the words “erythorbate” and “earthworms” has led to this confusion.