Zombies of the Deep
Monster Monday
November 16, 2015
Modern popular culture is virtually obsessed with zombies, undead creatures that roam the countryside in shambling hordes, looking for living victims to eat or infect. But at the bottom of the sea lurks an equally ghoulish creature, a real-life “zombie” called the zombie worm, waiting to feast on the bones of dead animals that fall to the ocean floor.
Zombie worms feast on the bones of dead whales. Credit: © MBARI
It is the female zombie worm that devours the fallen bones of whales and other sea creatures. She resembles a ghastly flower growing out of the bone. The “stem” is a hard tube that protects the female’s body, and the feathery red “blossom” acts as the zombie worm’s gills, taking oxygen from the water.
Most of the female’s body is actually inside the bone, where her “roots” dissolve the hard bone material away, taking in the nutritious tissue that remains. The female does not even “eat” this substance. Instead, she feeds it to bacteria living inside her body that, in turn, provide the zombie worm with nutrition.
Bacteria aren’t the only things living inside this zombie. The male zombie worm is thousands of times smaller than the female. And a “harem” of hundreds of males lives inside the female’s tube. There, the males fertilize the hundreds of eggs the female produces every day. The eggs become small swimming larvae (young), which must settle on bone to grow. Most larvae do not survive, as there are not many bones on the ocean floor.
Despite their ghoulish lifestyle, these undertakers of the deep play an important role in the ecology of the oceans. In eating away bone, the zombie worm helps to recover nutrients from the dead tissue, making them available for use by other living things.
