Sea Cucumbers

Description

Sea cucumbers are part of a larger animal group called echinoderms, which also contains starfish and sea urchins. Their body shape is similar to a cucumber, but they have small tentacle-like tube feet that are used for locomotion and feeding. One way that sea cucumbers can confuse or harm predators is by propelling their own toxic internal organs from their bodies in the direction of an attacker. The organs grow back, and it may save them from being eaten. Depending on the species, sea cucumbers normally vary in size from less than an inch (2.5 centimeters) to over six feet (1.8 meters).

Range

Sea cucumbers are found in virtually all marine environments throughout the world, from shallow to deep-sea environments. Sea cucumbers are benthic, meaning they live on the ocean floor. However, their larvae are planktonic, meaning they float in the ocean with the currents.

Diet

Sea cucumbers are scavengers that feed on small food items in the benthic zone (seafloor), as well as plankton floating in the water column. Algae, aquatic invertebrates, and waste particles make up their diet. They eat with tube feet that surround their mouths.

Life History

Sea cucumbers exhibit sexual and asexual reproduction. Unlike most terrestrial animals, sea cucumber eggs undergo external fertilization—females release eggs into the water that are fertilized when they come into contact with sperm that males have released. In order for this form of reproduction to be successful, many males and females must be together at the same time. A sea cucumber can live for 5 to 10 years.

Conservation

Sea cucumber populations are stable. They are regarded as delicacies in some countries.

Fun Fact

When disturbed, sea cucumbers can expose skeletal hooklike structures that make them harder for predators to eat.

Sources

Miami University

National Geographic

Tree of Life Web Project