A new crab species discovered in the Pacific Ocean near Costa Rica feeds off the bacteria on its claws fertilized by methane and sulfide released from the seafloor. Initially discovered in 2006, Kiwa puravida is only the second member of the Yeti crab family discovered to date according to Andrew Thurber, a post-doctoral researcher at Oregon State University that lead the study.

"We watched the crabs wave their claws back and forth in fluid from a methane seep, and rather than trying to capture bacteria, it appeared that they were providing food to the bacteria already growing on their claws," Thurber said. "There isn't sufficient food that deep that is derived from the sun's energy, so vent and seep animals harness chemical energy released from the seafloor."

Primary food source
Lipid and isotope analyses revealed epibiotic bacteria to be the crabs’ primary food source, though it is theorized they obtain a small degree of sun-derived energy from dead plankton filtering down through the water column. Thurber believes the crabs harvest bacteria growing on their claws by using a specially adapted appendage to scrape the bacteria off their bodies and bring it to their mouths, and then continually waving their claws near methane seeps to boost the bacteria’s productivity.

Only one specimen of the original Yeti crab, K. hirsuta discovered in 2005, has been collected and that was near a hydrothermal vent. About 30 to 40 Kiwa puravida specimens have been examined,with scientists believing them to exist at similar methane seeps."Since this entire family of crabs wasn’t even discovered until 2005, there is a strong possibility other species are out there," Thurber added.

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