The Bythograeidae are a small family of blind crabs which live around hydrothermal vents.

Bythograeidae are a monophyletic, sister taxon of the superfamily Xanthoidea which split to inhabit hydrothermal vents around the Eocene.

[4][5] Due to the lack of fossils found in this group the exact date of origin of Bythograeidae remains unknown.

Instead, organisms rely on Chemosynthetic bacteria to sustain the vast amounts of life in Chemotrophic ecosystems.

[9] Bythograeidae are omnivorous scavengers, they are believed to eat bacteria and other vent organisms however they can also be found far from active sites.