Is this the first time you’ve heard the name sea cucumbers? Well, they are not fruits. Sea cucumbers are, in fact, sea animals. They may not look like much, but they are more than capable of surviving in the deepest depths of the sea.
Let’s learn and explore “what do sea cucumbers eat?”
Sea Cucumbers Habits And Biology
Sea cucumbers (Holothuroidea) are marine animals with elongated bodies and leathery skin containing a single gonad (reproductive gland). They are named for their resemblance to the cucumber plant.
They are found worldwide on sea floors, shallow and deep. You can find the most significant numbers located in the Asian Pacific region. Humans gather sea cucumbers for consumption, otherwise known as aquaculture. The product harvested is known as trepan, belate, or namako.
Sea cucumbers play an essential role in marine ecosystems as they aid in recycling nutrients by breaking down detritus and other organic matter, after which bacteria can carry on the degradation process.
Sea cucumbers are usually 4-12 inches (10-30 centimeters) in length, the smallest of all being 3 millimeters long and the largest being 3 meters (10 feet) long.
Different species exhibit a variety of shapes, from some being spherical to others being worm-like and lacking arms. This trait is common in many other echinoderms, such as starfish.
The mouth is located at the front end of the sea cucumbers body, surrounded by a ring of retractable tentacles.
The tentacles are modified to serve as feet for movement. They can either be simple, tree-like or branched. In addition to the tentacles, some sea cucumbers have muscles that contract to aid in movement.
Most predators typically avoid sea cucumbers because of the toxins they produce and the unique defense systems. However, some predators like the Tonna galea and Tonna perdix paralyze them using a strong poison before swallowing them whole.
Some sea cucumbers, when threatened, shoot out sticky threads that trap their enemies, allowing them to escape. Also, they get rid of a better part of their internal organs from their anus to distract their enemies long enough to escape.
What Do Sea Cucumbers Eat In The Wild?
Sea cucumbers benthic feeders, meaning they live on the seafloor and get their food from there. Sea cucumbers use their retractable tentacles to trap food material and insert it in their mouths for digestion.
Sea cucumbers get their food by scavenging rather than tracking it down as they are not the best hunters. Being omnivores, they feed on both plants and animal matter, depending on what’s available.
When feeding, they use their feeding arms (tentacles) to get hold of particles in water. Alternatively, they plow them into the sand, eat them, and poop out useful clean valuable material to other marine life.
Burrowing sea cucumbers species ingest a lot of sediments (rocks, minerals/remains of plants and animals) from which they absorb nutrients.
Sea cucumbers are the earthworms of the sea. The poop they discharge is rich in calcium carbonate that aids in the formation of coral reefs.
Below is a list of what they typically eat every day for sustenance:
- Algae – (organism with no roots, stems, or leaves and mostly found on rivers).
- Planktons are a group of microorganisms found in water that can’t propel themselves against water currents. They serve as a ready meal for sea cucumbers.
- Fish as well as small marine animals.
- Waste particles, such as dead animal particles and other organic waste.
Recent discoveries show that sea cucumbers also benefit from feeding on seagrass and its sediments. Their diets vary from time to time following weather changes and their migration patterns.
When food is unavailable, sea cucumbers have a unique way of surviving. They will slowly feed on themselves. As a result, they shrink.
Facts About Sea Cucumbers
- Sea cucumbers don’t have a true brain. Instead, they have a variety of nerve endings found throughout the skin, giving them a sense of touch and a sensitivity to the presence of light.
- Aside from their intestines, sea cucumbers also use their tentacles to excrete nitrogenous waste through diffusion.
- Humans have been harvesting sea cucumbers for the past 170 years.
- In some Asian cultures, people consume raw sea cucumbers.
- About 30 species of sea cucumbers, including the red-chested sea cucumber, fertilize their eggs internally. They use their feeding tentacle to pick up the fertilized egg and place it into its pouch, where it develops and eventually hatches.
- Some animals and parasites live in sea cucumbers. This relation is known as symbiosis, where both animals benefit from each other. For example, a pearlfish can live in sea cucumber’s cloaca (anus), depending on it for shelter against predators and as a source of food.
- The Chinese use sea cucumbers in traditional medicine as it is said to have healing qualities used to treat ailments like cancer, frequent urination, impotence, and arthritis.
- When water temperatures become too hot, sea cucumbers aestivate. Aestivation is a state of dormancy where they stop feeding to slow down metabolism and lose weight. When temperatures improve, their bodies return to normal.
- Sea cucumbers are nocturnal, therefore, are active during the night.
- All sea cucumbers breathe through their anus.
- Pineapple sea cucumbers are an endangered species. You would easily recognize them by the growths they have on their bodies called teats. They are the most consumed species of sea cucumbers.
- Another endangered species includes sandfish; their population decrease is mainly due to excessive consumption. Due to this reason, numerous Asian hatcheries raise these species in tanks to restock the wild populations.
- A hatchery is a building where the hatching of fish or poultry eggs is regulated for commercial use.
- The longest sea cucumber species is known as the tiger tail. Tiger’s tail often exceeds lengths of six feet. Their names come from their numerous stripes that make it appear like a tiger’s tail.
- Giant California Sea Cucumbers are the most uniquely colored species, with reddish skin and orange growths.
- Sea cucumbers are capable of self-reproduction. That is, they can give rise to offspring without a partner. They, however, prefer to reproduce by mixing with other sea cucumbers.
- Sea cucumbers are fit for human consumption. Humans harvest them for food and medicinal purposes. Their ability to replace expelled organs almost immediately is being studied for its potential to repair human ligaments. A ligament is a tough fibrous tissue that gives the joints in your body support.
- Sea cucumbers can modify the shape of their bodies when the need arises. They can fit through tight spaces due to this feature.
- Sea stars and urchins are related to the sea cucumber. These marine animals all belong to a common group called echinoderms. Like other echinoderms, sea cucumbers have an anus in one end and a mouth in the other.
- Sea cucumber can reproduce asexually (without using sexual organs). Asexual reproduction occurs when the body splits into two or more parts/fragments. The separated bodies regenerate missing body parts to become whole.
- You will find sea cucumbers in large populations. On the coast of New Zealand, you can find 1000 of them per one square kilometer.
- The lifespan of sea cucumbers depends on their species. The majority of them live for an average of five to ten years in the wild.
- While adult sea cucumbers are benthic, living on the seafloor, their larvae (offspring) are planktonic and float in ocean currents.
- Sea cucumbers are in danger of extinction due to human consumption, especially by Asians. They are shipped and sold by vendors in Hong Kong and Singapore at outrageous prices.
- Sea cucumbers are used in the production of commercial products like medicine, shampoo, and toothpaste.
- When a sea cucumber loses a tentacle, it takes about three weeks to grow one back.
Frequently Asked Questions (FAQ)
What makes the sea cucumber unique from other echinoderms?
Most echinoderms spines are visible, whereas sea cucumbers have ossicles (small bones) embedded in their skin. These bones provide evidence to the clue of the species identity. You can examine the ossicles under a microscope.
Do sea cucumbers have eyes?
No. sea cucumbers neither have eyes nor faces. They only have a mouth, digestive tract, and anus that aid in th feeding process.
Can sea cucumbers lay eggs?
Yes, sea cucumbers can lay eggs. Their eggs undergo external fertilization. Females discharge their eggs into the water, which fuse with sperms produced by males for fertilization.
What’s the growth process of sea cucumbers?
After sea cucumbers release sperm and eggs into the water, where eggs fertilize, they develop a sea horse-like appearance. Their larvae (offspring) will spend a few weeks suspended in water.
There you have it! The answers to the question, “what do sea cucumbers eat?” and more.
Sea cucumbers may seem like simple organisms, but they play a crucial role in their environments. Also, they are a favored ingredient in Asian cuisines. Their high demand has led to a decline in their population.