The world’s heaviest worms thrive in an extreme environment.
Towering colonies of giant tubeworms (Riftia pachyptila) grow where hot, mineral-laden water flows out of the deep seafloor. Unlike most animals, they don’t eat; instead, bacteria living in their guts transform sulfur into energy for them.
As harsh as their environment is, giant tubeworms live surrounded by a community of other animals—and their size doesn’t necessarily protect them. Their gills, which resemble foot-long red feathers, can be a vulnerable target for predators. The worms can quickly retract their gills into the tube if a hungry predator, like a vent crab, ventures too close.
When volcanic activity deep below the seafloor changes, the hot water sometimes stops flowing. In this case, the entire worm colony may die off. But when new hot springs pop up in other areas—often dozens or even hundreds of miles away—the tubeworm larvae quickly colonize them. Researchers are not sure how the larvae find the new vents, but deep-sea biologists are revealing new findings with every research expedition to these iconic deep-sea communities.
Maximum size: 2 meters (6.6 feet)
Depth: 1,900–3,600 meters (6,200–11,800 feet)
Habitat: hydrothermal vents
Range: East Pacific Rise and Galapagos Islands
Diet: nutrition provided by symbiotic sulfur-oxidizing bacteria