Wild Harris

Sea Cucumbers

Sea cucumbers are curious looking animals, a bit like a sausage with tentacles at one end. Most species found around our coast live in crevices in the rock where their spiny bodies are useful for jamming themselves in; the tentacles extend into the water where they trap passing food particles which are passed to the mouth.

sea cucumber in crevice_1926172355.jpgSea Cucumber    (Photo: Paul Tyler)

Only the head end of this sea cucumber is visible - the main part of its body is firmly wedged in a crack in the rock.


Occasionally a large black sea cucumber will turn up during the summer, especially on western coasts and around St Kilda. This does not bury itself; instead it roams around hoovering up anything it can find lying on the rock surface. Its common name, the cotton spinner, comes from its bizarre way of defending itself. The body of this animal is covered in spines that eject white sticky threads if it is disturbed (many sea anemones can do this too). If this doesn’t work, it resorts to an extreme action – it turns itself inside out! All its guts and innards come pouring out, and presumably this disgusting display is supposed to scare away the predator. It doesn’t die, however, it grows back its internal organs, although it will take many weeks before its back to normal.

Holothuria forskalii.jpgSea Cucumber -Holothuria forskalii    (Photo: Paul Tyler)

A rare visitor from warmer seas, the cotton spinner sea cucumber has an extraordinary method of warding off attackers.

by Paul Tyler