Sea cucumbers expel their internal organs through their anus to distract and ward off predators. They also evacuate their organs on a seasonal basis, regenerating them afterwards. In addition, some sea cucumbers have special, sticky tubules, part of their respiratory system, which they spew at predators.
Humans hunt sea cucumbers both as a food source and a seasoning. Most consumption of sea cucumbers occurs in Asia, with some species at risk of extinction from over fishing. Their absence in some habitats can be extremely detrimental to other sea life as well. Sea cucumbers process huge amounts of organic sediment on the ocean floor, and so serve a critical role in their ecosystems.