These worms truly are gigantic, and can grow to lengths of roughly eight feet. They are characterized by their bright red "plume" which is actually a hemoglobin-rich organ that siphons chemicals to the bacteria. The outer tube of the worm is comprised of chitin, the same material that makes up the exoskeletons of crustaceans. When threatened, the plume will retract in to the tube.
Giant Tube Worms reproduce through spawning; eggs are released into the water and are then fertilized. Young worms then eventually hatch and attach themselves within a worm community. No one is really sure how the young worms obtain their symbiotic bacteria, or how they find vents to attach themselves near. We do know, however, that Giant Tube Worms have remarkable growth rate, as they are able to reach a length of about five feet in roughly two years.