Nutrition - Diet
Because Kiwa hirsuta is such a recently discovered species, in situ observations of Yeti crabs remain scarce. Not surprisingly, therefore, little is known definitively about the dietary habits of the species.
Macpherson, et al. (2005) recorded images of Yeti crabs roaming the vent mussel beds near hydrothermal events. In addition, they observed Yeti crabs preying on vent mussels whose shells had been damaged by the submersible apparatus used to collect specimens, leading them to theorize that K. hirsuta is "probably omnivorous," feeding primarily on algae and animal species.
In a 2006 interview with BBC Online, species discoverer Dr. Michel Segonzac reiterated this assessment. He described K. hirsuta as a "general carnivore," relating that he had once observed two Yeti crabs fighting over shrimp.
According to the Census of Marine Life, sponsored by the Office of Marine Programs at the University of Rhode Island, omnivory is indeed the normal dietary pattern for most decapod species.
Several species of filamentous epibiotic bacteria intertwine themselves in K. hirsuta's luxuriant mats of flexible setae. Despite the finding of Goffredi, et al. (2008) that these bacterial species may be capable of carbon fixation and sulfur cycling, the nature of the relationship between K. hirsuta and the bacteria remains unclear. Dr. Segonzac hypothesized that K. hirsuta may prey on the bacteria, while other researchers speculate that that the bacteria filter impurities from the water.
The Yeti crab possesses a remarkable digestive system and circulatory system to process the nutrients it ingests.