I thought there were hundreds of Nucella snails gathered at the base of a large boulder during the minus tide. It turned out to be Pagurus hirsutiusculus (Hairy Hermit Crab) inside the empty shells. I didn't know they congregated in such large numbers.
This 1" Lophopanopeus bellus bellus (Black-clawed crab; aka Blackclaw crestleg crab) was lounging inside an empty Giant Acorn Barnacle shell.
No live ones seen, but plenty of fresh claws and red Heerman's Gull poop.
Benthic surveys, Elkhorn Slough
The decapods or Decapoda (literally "ten-footed") are an order of crustaceans within the class Malacostraca, including many familiar groups, such as crayfish, crabs, lobsters, prawns and shrimp. Most decapods are scavengers. The order is estimated to contain nearly 15,000 species in around 2,700 genera, with approximately 3,300 fossil species. Nearly half of these species are crabs, with the shrimp (c. 3000 species) and Anomura (including hermit crabs, porcelain crabs, squat lobsters: (c. 2500 species), making up the bulk...