Sea Cucumber

The sea cucumber, or the Holothuroidea, is an echinoderm, akin to sea urchins and starfish, and is a worm-like creature with usually a soft body. They are called sea cucumbers because they do resemble cucumbers. They can be found practically in every marine environment, although tropical coral reefs that exist in shallow water are where they are found in the most diverse abundance. While all sea cucumbers dwell in the ocean, their habitat can range from intertidal areas, where they can be exposed when the tide ebbs to the deepest of ocean floors. They inhabit the floor of the ocean, sometimes partially burying themselves inside it. The sea cucumber crawls across the floor of the sea using hundreds of minute suction cups in their tubular feet.

Various Types of Sea Cucumbers

The oldest sea cucumber fossils are of spicules, which date back to the Silurian period, about 425 million to 405 million years back, which makes the sea cucumber a very ancient creature indeed. Since then, there has been a considerable amount of diversification that has taken place, with about 1400 species in existence today, in various forms. While the adults of some midget species of cucumbers may not be more than a single centimeter, others can measure up to 20 cm in length. One species of large sized sea cucumbers, the Synapta maculata, can grow up to 5 m in length. While many of the species of sea cucumbers can swim, there are even types that live like plankton all their lives, floating with the currents of the ocean.

The three most common types of sea cucumbers are: the white star cucumber; the California cucumber; and the warty sea cucumber. The color of the white sea cucumber ranges from white to light orange, and it has non-retractable, long spines that cover its body, and they grow up to 4 inches in length. The California sea cucumber’s color ranges from reddish brown to brown, and its body is covered with cone-like, pointed projections. This species grows up to 16 inches in length. The color of the warty sea cucumber is chestnut brown, and it has black-tipped wart-like growths all over its body. These grow up to 10 inches in length.

The Feeding Habits of the Sea Cucumber

Generally, sea cucumbers are scavengers, making a meal of the debris at the bottom of the ocean. Most sea cucumbers feed on decaying organic matter that occurs in the sea, tiny algae, plankton, and minute marine animals, which they collect with their 8- to 30-foot long tubular feet, which surround their mouth, and look like tentacles. Sometimes they also sift through the sediments at the bottom with their tentacles. The food that the sea cucumber eats is broken down into even smaller particulate matter, which in turn becomes food for bacteria, thus they help in recycling them back into the ecosystem of the ocean.

The Breeding Habits of the Sea Cucumber

Sea cucumbers have the ability of breeding both asexually as well as sexually. Although, typically they tend to reproduce sexually, however, it is not a particularly intimate process. Both sperm and eggs are released into the water and fertilization takes place when they meet. For this method of reproduction to be successful, it is important for there to be many sea cucumbers in a population of these animals. This indeed can be seen in many areas of the ocean depth, where these ancient creatures occur in large herds, feeding on the microscopic organisms of the aquatic waters.

The Defense Mechanism of Sea Cucumbers

When they feel threatened, some species of cucumbers have the ability of discharging sticky threads with which they trap their enemies. Other species even go to the extent of mutilating their bodies as a mechanism of defense. They do this by violently contracting their muscles and jettisoning a part of their innards through their anus. These ejected parts of the body are regenerated very quickly.

Various types of fish as well as other aquatic animals prey on sea cucumbers, especially their eggs and larvae. Some Asian people also farm some of the species of sea cucumbers, which they consider as delicacies.