All Aboard the Sea-Cucumber Train!

Life on the seabed is harsh, brutish and wet, but these juvenile King Crabs have discovered an amazing way of dealing with the dangers.

The seabed is for the most part, featureless and flat, which means that there isn’t much cover for young crabs to hide from predators.

Which is where the humble sea-cucumber comes in. First things first though, sea-cucumbers aren’t cucumbers like the plastic coated ones in Tesco, or even the knobbly ones your Nan grows.

They’re actually echinoderms and are in the same class of animals as starfish. They are really important to the marine ecosystem and help clear and recycle debris from the ocean floor. They have numerous tube-like feet that allow them to move across the sea floor, slurping up goodies as they go.

The largest known species can reach a whopping 3 metres long!

For young crabs though, these meandering sea creatures are a squidgy taxi service and they cling on underneath them. Alongside the benefits of transport, these animals provide some of the only cover from predators on the open sea floor.

Researchers examined 2600 sea-cucumbers and found that nearly a quarter of them had a juvenile crab clinging onto their underside. More strikingly though, 96% of crabs they found had an associated sea-cucumber.

Nature often works in partnership, in what we call symbiotic relationships, but in this case, scientists are not sure if the sea-cucumber gains anything at all.