Digestive tract

Though as with most most crustaceans (and predators in general), the straight-through ailimentary canal (digestive tract) of the Yeti crab is relatively short, it is also surprisingly complex, comprising three general sections: foregut, midgut, and hindgut.

Adapted from http://bio.classes.ucsc.edu/bio136/LabManual/Emerita/emerita.pdf
Model decapod digestive system.  Items salient to this discussion include abdominal muscles (A), gastric mill (B), diverticulum (E), midgut (F), gills (H), and hindgut (J). 
(Courtesy Dr. Marinovic © 2009)

Food passes from the buccal cavity (mouth) down a brief esophagus into the foregut, where it enters through a stomach that consists of two pouches.  The next stop along the digestive path is a complex muscular structure known as the gastric mill, constructed of calceous plates (ossicles) that grind together like teeth to break down food into small particles.  An adjoining cluster of rigid, chitinous setae filters out excessively large food particles, returning them to the gastric mill for further processing (Ceccaldi 1989).

Food particles fine enough to flow through the setae filter pass into the midgut, where they are further digested by glandular secretions in a series of pouches known as diverticula.  Transit time in the highly acidic environment of the diverticula is astonishingly fast—less than one minute in most cases (Ceccaldi 1989).  (By contrast, typical transit times in the human gut are from 12 to 36 hours.)

The short hindgut (intestine) terminates in a muscular anal sphincter that controls waste excretion. In many crustacean species, the anal sphincter also has the remarkable ability to pump water back into the gut prior to defecation!  This strange phenomenon, known as "anal swallowing," apparently performs a function similar to that of a salt-water enema (Fox 1952). Since so few live specimens of K. hirsuta have been collected, it remains to be seen whether the Yeti crab also indulges in this bizarre activity.

Nutrients are absorbed from the digestive tract into the cardiovascular system, where they are delivered to tissues throughout the body.

Nutrition - Diet