Polychaetes (bristle worms), survive intense sea pressures where sunlight never penetrates. Instead of a barren wasteland on the ocean floor, scientists have discovered diverse communities of creatures that live on and around hydrothermal vents. These scale worms are hosts to symbiotic bacteria that may be providing them with nutrients. "The deep sea realm is one of the most diverse habitats on Earth, yet our perception of it is still in its infancy," says Daniel Desbruyeres, a senior researcher at Ifremer, France.