My favorite creatures in the ocean are the weird ones. Those blobby, slippery, bizarre, alien-looking things that make you wonder “How does that live on our planet with us?” They remind me that the slice of nature I get to see is just a small fraction of the life out there. The Earth is a weird place, and that’s what makes it wonderful. 

And that’s why it gives me such great pleasure to introduce you to one of these strange and glorious creatures: the swimming sea cucumber, also known as the headless chicken monster. This curious creature is a beautiful deep red color with fins that look like a fringed veil, giving it a vibe that might best belong in Dracula’s castle. These sea cucumbers are on the large side, averaging about nine inches in length, compared to their smaller fellow sea cucumbers. They can be found in the benthic zone, the sandy bottom of the ocean. 

People who see these creatures have mixed reactions with some finding them beautiful, strange or terrifying. This mixed reaction is reflected in the many different names people have for them. Their scientific name is Enypniastes eximia which means the “dreamer sea cucumber.” Their common name is the swimming sea cucumber which reflects the fact that this species is unusually mobile compared to its other sea-cucumber cousins. They have unique webbed fin-like structures that not only help them move but make them look cool while doing so. 

The other names for the swimming sea cucumber get a little weird, which is understandable when trying to find a title befitting such a peculiar creature. Some call the creature a Spanish dancer after the way it gracefully moves through the ocean with its red frills waving around (not to be confused with the Spanish dancer nudibranch, another swimming invertebrate). Others call it the pink sea-through fantasia due to its rosy hue and transparent body. The most shocking name this sea cucumber has earned is the “headless chicken monster.” This moniker came from ROV pilots who saw swimming sea cucumbers in the deep sea and thought they looked chickens right before going in the oven. 

These sea cucumbers spend most of their time walking along the ocean floor. Their tentacles both move them and help them scoop up sand to allow them to eat the detritus they find there. Their transparent bodies mean that the food they eat can be tracked through their digestive systems. Just because they prefer to lie on the sandy bottom doesn’t mean they can’t move when needed; these swimming sea cucumbers can travel up the water column to find new food sources and to avoid predators. 

As much as I’d love to tell you more about these chicken monsters, there aren’t many more known details because of where they live. It’s hard to study animals that can live miles below the ocean surface and well below the maximum depths human divers can reach. There have been only a few recorded sightings of these swimming sea cucumbers! They are incredible reminders of all the fascinating deep-sea creatures that live in our ocean and are only rarely seen like the blob fish or glass octopus. If you are curious about what else the ocean is hiding in its depths, you can explore more deep-sea creatures here.

The last place these mysterious ocean creatures were spotted were in the deep seas near Chile. Climate change affects all levels in the ocean, even the depths where these swimming sea cucumbers roam. We hope these weird and wonderful creatures spotlight why it is so important to take climate action now to protect our planet. Join Ocean Conservancy in protecting our ocean for all the creatures that live in it, even those we might not commonly see.