Marine worms
Giant tube worm
Riftia pachyptila
Harmless🌊 1500–2500 m📏 up to 200 cmIUCN status: Not evaluated
Lacking a mouth, stomach or anus, it lives entirely thanks to symbiotic bacteria that convert the toxic hydrogen sulfide of hydrothermal plumes into energy.
🗺️ Geographic range
Hydrothermal vents of the East Pacific Rise, first discovered near the Galápagos Islands.
📊 Population
No population estimate available; colonies around hydrothermal vents are dense but geographically very localised and not evaluated by the IUCN.
Habitat
- Pacific Ocean · Hydrothermal vents · Bathypelagic zone · Permanent
Behaviour
- Diet
- No direct feeding: hosts chemosynthetic bacteria that nourish it by oxidising the toxic hydrogen sulfide from the hydrothermal plume.
- Hunting
- None: motionless, anchored to the seafloor.
- Reproduction
- Releases sperm and eggs into the water; external fertilisation.
Physiology
- Anatomy
- A bright red plume rich in hemoglobin, protruding from a protective white tube.
- Adaptations
- Can grow more than a metre per year, one of the fastest growth rates known in any invertebrate.
⚡ Its extraordinary abilities
- Lives without a mouth or stomach, entirely nourished by internal symbiotic bacteria
- Its hemoglobin carries both oxygen and a deadly poison without harm, a unique biochemical feat
🏆 Records
The fastest growth rate known in a marine invertebrate
Can grow more than a metre per year.
Source: Ifremer
🧭 Historical expeditions
If you cross paths with this animal…
Risk: None: inaccessible without a submersible, lives near vents exceeding 300°C.
Behaviour: Motionless.
Advice: A symbol of chemosynthetic ecosystems: proof that life can exist without sunlight.
💡 Did you know?
- Can grow more than a metre per year, one of the fastest growth rates in the animal kingdom.
- Its 1977 discovery near the Galápagos revolutionised biology by proving an ecosystem can thrive without sunlight.