Learn about the sea cucumber, its habitat, diet and more.
A Sea Cucumber normally lives in tide pool floors, shallow waters, muddy and sandy places. Did you know that some Sea Cucumbers live in polluted water? A Sea Cucumber normally lives in extreme low tide to 90m sub-tidal depths.
Some Sea Cucumbers are kept as pets in reef aquariums but often feared of killing other creatures in the aquarium because of the Sea Cucumbers defense mechanism.
The Sea Cucumber is an Echinoderm (Phylum Echinodermata) and is also an Invertebrate. Sea Cucumbers belong to the family “Holothuroidea”. There are approximately 1,150 described species of Sea Cucumber of which most are marine and distributed worldwide. Genus Pseudocolochirus are among the most poisonous Sea Cucumbers in the World. Sea Cucumbers are Macro-benthos along with Clams, Oysters and Starfish.
If a creature is a Macro-benthos it means that it lives on the ocean floor and are larger than one millimeter. The Giant Red or California Sea Cucumber is the largest member of the family Holothuroidea, and a relative of Sea Urchins, Sand Dollars, Starfish, Brittle Stars, and other Echinoderms. Three common Sea Cucumbers are the Warty Sea Cucumber, the California Sea Cucumber, and the White Star Sea Cucumber. Sea Cucumbers belong to the kingdom of Animalia (or the kingdom of animals.)
Sea Cucumbers have small suction tubes covering most of its body to help them move. Most Sea Cucumbers are colored brown and black but there are others that are different colors like white, orange and green. Sea Cucumbers have a special ability to contract their muscles, which allows them to shoot out water that they absorb and some of them can even shoot out their insides and grow them back as a defense mechanism.
Sea Cucumbers do understandably look like Cucumbers and that’s how their name originates. Sea Cucumbers extract oxygen from water in a pair of lungs that branch off the cloaca just inside the anus, so that they breathe by drawing water in through the anus and then expelling it. Sea Cucumbers do not have arms or legs. Some tropical species have thick, muscular body walls, whereas many deep-sea forms are gelatinous and transparent.
Sea Cucumbers, with the exception of members of Elasipodida and Apodida, have respiratory trees used in gas exchange. These structures are paired, heavily branched tubes inside the body cavity that attach to the rectum. These structures allow a type of breathing called cloacal breathing also present in an unrelated group, the Echiuran Worms. These nocturnal animals have a life span of about 5-10 years.
Sea Cucumbers eat the tiny scrap particles that are usually abundant in the environments that they inhabit. Sea Cucumbers have two different types of feeding. One of these is “direct deposit feeding.” In this feeding method, Sea Cucumbers literally wipe their tentacles over the sediments to pick up tiny particles that settle there from the water above. The other mode of feeding is the suspension feeding. Suspension feeding Sea Cucumbers have fine buccal tentacles that are used to pick particles out of the water column during feeding.
Sea Cucumbers tend to have separate sexes and spawning behaviour tends to be seasonal. During spawning, Sea Cucumbers travel to the top of reef structures and release their gametes into the surrounding currents. A range of developmental modes is seen among Sea Cucumbers. Development via feeding larvae (Planktotrophy) or non-feeding larvae (Lecithotrophy) occurs in a large number of species. In others, embryos and larvae may be brooded by the female. The feeding larva of Sea Cucumbers (when present) is very distinctive and is called an “Auricularia” larva. It swims for about 10-40 days before settling on the bottom and develops into a baby Sea Cucumber.
Did You Know?
There is a little fish that lives in the back end of Sea Cucumbers? In return for being a cleaner, the fish gets a place to live and something to eat.
Indigenous Australians of the North-West of Australia used to export Sea Cucumbers to the Chinese who still is a large importer of Sea Cucumbers? Sea Cucumbers became our first export supply.