That distinction goes to a tapeworm that lives in the intestines of whales. This species is a fairly new discovery. Scientists learned about it in the 1980s. The worms live in clusters of millions, covering acres of ocean floor. Each worm is protected by a thin, flexible, shell-like tube.
Some tortoises live even longer.
And marine biologist Charles Fisher said colonies of coral live for centuries. But Lamellibrachia hold the age record for a single invertebrate organism, he said. Finding out the age of a giant sea worm is a bit more complex than counting the rings of a tree. Fisher and his colleagues rode a submarine to the bottom of the gulf, where they used robotic arms to mark the ends of the tubes. Three months later, they returned and measured how much the worms had grown.