Picture it: You’re startled awake in the middle of the night. You peek out the window and see that the only light is that of the full moon. What woke you? Then you hear it. The shuffling of feet outside the bedroom door. Low groaning—or is it a growl? What’s out there? An animal? A person? A… dare we say it… zombie?

You throw the door open, ready to face your fate. With a sigh of relief, you realize it’s just a family member, sleepwalking again. After helping them back to bed, you settle back in. No longer afraid, you remind yourself that zombies aren’t real. They only exist in graphic novels and scary movies.

Or do they? Ask any marine scientist, and they’ll tell you about an animal that may make you reconsider what you think you know about zombies. What are we talking about? Oh, only today’s Wonder of the Day—the zombie worm!

Do zombie worms growl for “braaaiins” like fictional human zombies? No, these unique creatures don’t much resemble their stumbling namesake. If zombie worms could speak, they’d be more likely to groan, “Booooones!”

Specifically, zombie worms crave whale bones. That’s where their scientific name—Osedax—came from. It’s Latin for “bone devourer.” And that’s exactly what zombie worms do. They feed on the skeletons of dead whales that have fallen to the ocean floor.

If you ever see a zombie worm in person, you might WONDER how exactly they eat. After all, these deep-sea animals don’t have mouths. In fact, they don’t even have stomachs. Instead, zombie worms have root systems, much like plants. Their roots bore into bones and digest the nutritious fats and oils inside. 

Do humans need to worry about these mouthless, bone-eating creatures? No, not at all. For one thing, they’re much more interested in whale bones than they are in people. In fact, they probably don’t even know humans exist. Zombie worms live deep in the ocean, up to 13,000 feet (4,000 meters) below the surface. 

How long have Osedax worms been feasting on whale remains? Many experts say as long as whales have been around, so have zombie worms. Currently, the oldest evidence of zombie worms is a 30 million-year-old whale bone.

Of course, evidence of other bone-eating organisms goes back even further. It seems that animals have been eating each other’s remains for most of Earth’s history. It’s no surprise that the idea has made its way into popular culture! Maybe those fictional, hungry zombies aren’t so out of this world after all.