These nocturnal animals have a life span of about 5 to 10 years. These echinoderms have no arms, but do have five-part symmetry. A sea cucumber breathes by pumping sea water in and out of an internal organ called a respiratory tree. Some sea cucumbers burrow into the sea floor. Sea cucumbers have no brain.
Sea cucumbers eat decaying matter that floats in the water or is in the sand.
Sea turtles, crustaceans, many fish, and people eat sea cucumbers. They can expel most of its internal organs to confuse predators - it later regrows the organs. Some sea cucumbesr' bodies contain toxins that can deter attackers. When an egg is fertilized and hatches, the tiny planktonic larva drifts with the ocean currents. It will eventually settle onto the sea floor and develop into an adult.