Sea cucumbers are football shaped creatures that lay on their side at the bottom of the ocean. They have 5 rows of tube feet running lengthwise. Its mouth is surrounded by tentacles that are really tubed feet. Unlike sea stars, the vascular system is not filled with sea water. Instead, sea cucumbers use a special body fluid.
Sea cucumbers eat plankton and other organic matter.
Some position themselves in a current that brings a steady supply of food, and spend hours there. The tentacles are opened up and collect food in the current. The sea cucumber brings each tentacle to its mouth and licks it, while the other tentacles go on collecting food. Other sea cucumbers feed by sifting through sand using their tentacles. Many sea cucumbers are poisonous.