Giant California sea cucumber Parastichopus californicus uses anus as a second mouth.

Previously, scientists knew, shallow marine invertebrates that live near the Pacific coast of North America, using the anus for breathing.
 
Because they have no lungs, breathing used vodnososudistaya ambulacral system, which consists of a plurality of channels extending throughout the body. Branched bags through which breathing goloturii receive oxygen when water is injected into the anus by rectal muscle.

Scientists William Dzhekl from Illinois Wesleyan University and Richard Strathmann (Richard Strathmann) from the University of Washington decided to further explore these creatures.

As it turned out, the guinea ourtsov system of blood vessels connecting the breathing bags branched intestine, is not for the transport of oxygen to the intestine. Scientists believe that this structure is necessary for the transfer of food from the intestine to the anus, and not vice versa, as is common in animals.