Sea Cucumber

Sea Cucumber Facts
Size 4-12 inch (10-30 cm)
Speed Unknown
Weight Unknown
Lifespan 5-10 years
Food Plankton
Predators Starfish, fish, crabs
Habitat In oceans worldwide
Phylum Echinodermata
Class Sea cucumbers
Scientific name Holothuroidea
Characteristics Long, worm-like animal

Sea cucumbers are not a kind of vegetable, but animals. They are named sea cucumbers because of the shape of their body, which resembles a cucumber. There are more than 1,200 species of sea cucumbers. Most of the time they live on the ground of the sea.

Quite Massy

In ocean depths of 4-5.5 miles (8-9 km), sea cucumbers make up about 90 % of the “biomass” (= mass/amount of living creatures per sector).

Sociable Sea Cucumbers

The red strawberry sea cucumber lives in groups of up to 93 animals per square feet (1,000 animals per square meter). In their home region New Zealand such colonies are also called strawberry fields.

Sea Cucumber Sea Cucumber - Photo: Ethan Daniels/Shutterstock

Unique Respiration

Sea cucumbers have a unique way to breathe. They have two respiratory “trees” that branch off their cloaca into their body. The animals breathe by sucking in water through their anus and distribute it into the treelike branches in order to retrieve the oxygen from it.


The respiratory system of the sea cucumber is quite unusual – or to put it more bluntly: disgusting for us humans. The sea cucumber’s manner of defense is equally nasty: It ejects its intestines. Who would not be confused by this? Enemies are stunned for a little while until they understand what’s going on – enough time for the sea cucumber to make an escape. Sometimes the sea cucumber also ejects its intestines to get rid of parasites. It simply reproduces itself afterwards (!). Another method of defense is to emit slime which is so sticky that you need a knife to scrape it off.

Sea Cucumber Sea Cucumber - Photo: unterwegs/Shutterstock

The Biggest and the Smallest

There are about 1,200 species of sea cucumbers. The smallest is 0.1 inch (3 mm) long and the longest 3-6.5 ft (1-2 m) with a diameter of 9.4 inch (24 cm).


Female sea cucumbers eject their eggs into the water and the males do the same with their semen. The eggs get fertilized by the semen. Some sea cucumber species can also reproduce by fission.

Sea Cucumber Sea Cucumber - Photo: Erin Wildermuth/Shutterstock

Sea Cucumber Sea Cucumber - Photo: e2dan/Shutterstock

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