Pacific sand crab (Emerita analoga) partially buried in sand. The front of this crab is at left. It inhabits the inter tidal zone of the Pacific coast of the Americas, from Alaska down to Chile. It is often found in dense aggregations, all moving simultaneously to keep up with the tide. It is a filter-feeder, sifting small plankton particles from the surf using its hairy antennae (not seen). It is a small crab, reaching a maximum length of only around 3 centimeters.