Giant tube worm

The giant tube worm is one of the most astonishing creatures in the whole ocean. It lives deep, deep down on the seafloor, far below where any sunlight can reach, in a world of total darkness. There it grows inside a long white tube, standing tall like a strange undersea plant — but it is truly an animal, a giant relative of the earthworms in your garden.

These worms cluster around hydrothermal vents, which are like hot springs on the bottom of the sea. Warm, mineral-rich water bubbles up from cracks in the ocean floor, and the tube worms gather right where it flows. They live around vents in the Pacific Ocean, near places like the Galapagos Islands and the East Pacific Rise, sometimes in patches many metres wide.

Here comes the most amazing part: a grown giant tube worm has no mouth and no stomach at all. So how does it eat? Living inside its body are billions of tiny helpful bacteria. The worm gathers chemicals from the vent water, passes them to the bacteria, and the bacteria make food and share it back. It is a perfect partnership, and it lets the worm feed without ever taking a bite.

At the top of each white tube waves a soft, feathery plume, and it is a beautiful bright red — red for the very same reason our own blood is red. The worm uses this plume to soak up the chemicals its bacteria need. When something drifts too close, the worm can quickly tuck its plume safely back inside its tube.

Giant tube worms were only discovered in 1977, when scientists in a tiny submarine explored the deep sea near the Galapagos and found a garden of them glowing red in the dark. They grow faster than any other animal on the seafloor. Living so deep, they have never been given a conservation rating, but they remain one of the most wonderful surprises the ocean has ever shown us.