The Sea Cucumber. Holothuroidea. A few facts before the video demonstrating the incredible creature.
Holothuroidea are generally scavengers, feeding on debris in the benthic zone of the ocean. Exceptions include pelagic cucumbers and the species Rynkatropa pawsoni, which has a commensal relationship with deep-sea anglerfish. The diet of most cucumbers consists of plankton and decaying organic matter found in the sea. Some sea cucumbers position themselves in currents and catch food that flows by with their open tentacles. They also sift through the bottom sediments using their tentacles.
A remarkable feature of these animals is the catch collagen that forms their body wall. This can loosened and tightened at will and if the animal wants to squeeze through a small gap it can essentially liquefy its body and pout into the space. To keep itself safe in these crevices and cracks the sea cucumber hooks up all its collagen fibres to make its body firm again.
Disappearing Sea Plant
March 20, 2008
Sea cucumbers are echinoderms—like starfish and sea urchins. There are some 1,250 known species, and many of these animals are indeed shaped like soft-bodied cucumbers. All sea cucumbers are ocean dwellers, though some inhabit the shallows and others live in the deep ocean. They live on or near the ocean floor—sometimes partially buried beneath it.
Sea cucumbers feed on tiny particles like algae, minute aquatic animals, or waste materials, which they gather in with 8 to 30 tube feet that look like tentacles surrounding their mouths. The animals break down these particles into even smaller pieces, which become fodder for bacteria, and thus recycle them back into the ocean ecosystem. Earthworms perform a similar function in terrestrial ecosystems.
Sea cucumbers, particularly eggs and young larvae, are prey for fish and other marine animals. They are also enjoyed by humans, especially in Asia, and some species are farmed as delicacies.
When threatened, some sea cucumbers discharge sticky threads to ensnare their enemies. Others can mutilate their own bodies as a defense mechanism. They violently contract their muscles and jettison some of their internal organs out of their anus. The missing body parts are quickly regenerated.
Sea cucumbers can breed sexually or asexually. Sexual reproduction is more typical, but the process is not very intimate. The animals release both eggs and sperm into the water and fertilization occurs when they meet. There must be many individuals in a sea cucumber population for this reproductive method to be successful. Indeed, many parts of the deep ocean host large herds of these ancient animals, grazing on the microscopic bounty of marine waters.