Most kindergarteners can tell you that an animal eats with its mouth, not its butt.
One species of sea cucumber, however, didn’t appear to get the memo: Scientists have discovered that the giant California sea cucumber (Parastichopus californicus) actually uses its anus as a second mouth.
Scientists already knew that the marine invertebrate, which lives in the shallow ocean waters off the Pacific coast of North America, breathes with its butt. Because they don’t have lungs, sea cucumbers rely on respiratory trees, a set of long tubes running down either side of the body with a lot of different branches. P. californicus is shaped like a hollow tube, with a mouth at one end and its anus at the other.
The respiratory trees receive oxygen when water is pumped through their anus using the muscles of their cloaca, an opening at the end of the intestinal tract.The 20 in. long (50-cm-long) animal is no slouch: It can pump 3.5 to 4 cups of water per hour through its anus, transferring the oxygen from the water into its respiratory trees, which then oxygenates its cells…