Blood worms are marine segmented worms which belong to the Annelid group. They are mostly found on the eastern coast of America.
They can be up to 37 cm in length, their growth rate is affected by the amount of food available and the temperature and saltiness of the sea.
Blood worms live in tubelike structure built on rocks underwater. They are excellent burrowers.

On their segments bloodworms have small fleshy projections or outgrowths called parapodia, which help them to move. The parapodia also contain gills which the worms use to exchange gases between their body fluids and the water surrounding them. They have strong jaws containing copper as well as poison glands to kill prey. Their bit is painful but not deadly to humans.
Their name comes from the red body fluid which is visible through their pale skin.
To avoid overcrowding during the winter months Bloodworms redistribute themselves around the sea.
After they mate the female dies. They have several predators including Crustaceans, carnivorous worms, some types of fish and seagulls.