Sea cucumbers

Sea cucumbers

Cotton spinner © Paul Naylor/

Strange sea creatures

They're sausage-shaped and have no brain, but that's where the similarity with cucumbers ends! These strange sea animals are related to starfish and make their homes on sea floors all over the world, including right here in the UK.

Sea cucumber

Sea cucumber © Paul Naylor/

Feathered feeders

Some sea cucumbers burrow into sand with just their feathery tentacles sticking out, catching tiny bits of food drifting by in the water. They bring their tentacles into their mouth one by one and collect the food from them - like when you lick your fingers. Yum!

Cotton-spinner sea cucumber

Cotton-spinner sea cucumber © Paul Naylor/

Sand scavengers

Other sea cucumbers ramble about on rows of little feet, sifting through the sand to find food. They clean up the seabed by eating detritus (little pieces of dead plants and animals, and poo - tasty!). As they move around, these marine munchers leave behind their own poo, which provides nutrients for other ocean wildlife like corals and seagrass.

Cotton spinner exuding its guts

Cotton spinner squirting out organs © Paul Naylor /

Gut launchers

Sea cucumbers have clever ways to avoid becoming dinner for other animals. They can make their bodies squishy or hard - handy for squeezing through a small gap or wedging yourself into a crack to hide! If a predator gets too close, some species can distract them by squirting out their internal organs in a sticky mess! (Don't worry - the organs regrow in a few weeks.)

Sea cucumber (Psolus phantapus)

Sea cucumber © Paul Naylor/

Bum breathers

How do you breathe when you've got no nose? Use your bum! Sea cucumbers suck in water through their bum, take in the oxygen from the water, then spit it out again. Some types even have little fish living inside them, swimming in and out through their bottom. Some fish are harmless but others nibble at the sea cucumber's insides!