Worm Anatomy
A worms body is made up of many segments called ‘annuli’. The length of a worms body has muscles which contract and relax which enables the worm to move along a surface. The ‘annuli’ are covered in tiny hairs called ‘setae’ which help the worms movement. Worms have no lungs, so they do not breathe like a human being or like many other animals. Instead, because they do need oxygen, they absorb the air through tiny pores in the skin and it goes straight into their bloodstream.
A worms skin must stay wet so the absorbing can take place, that is why they have a constant slimy look. However, if they have too much water, they can drown.
Worms also have no eyes, ears or nose so they cannot see, hear or smell. Worms do however, have light-detecting cells on their bodies that can detect harmful light conditions. The ultra-violet rays of the sun are harmful to worms – they can even kill them, that is why worms spend most of their time underneath the surface of the ground. A worm is also very sensitive to movement and can sense rain approaching and other creatures who might be a danger to them.
Believe it or not, a worm has actually got five hearts. Five hearts that pump blood around its’ body.
On the right, you will see how a worm looks inside. You can see the five hearts lined up down the centre of the worms insides, just below the oesophagus.
There is a common myth that has been around for a long time now that if you cut a worm in half, the two halves will grow into worms – making 2 worms out of 1. This is very untrue. It is true that if a worm loses part of its body it will survive, but if you cut a worm into 2 pieces, one half will surely die. The half with the saddle (the fatter, pink part) will burrow itself into the soil and survive. It is not a good idea to cut worms in half or any other creature for that matter – it is very cruel – so please do not be taken in by this myth and leave the worms whole.