Horseshoe SOS is an identification and reporting app that includes a stunning gallery of horseshoe crabs, eggs, spawning and molts. Learn the anatomy of the Atlantic horseshoe crab and how horseshoe crabs differ from true crabs (hint: they aren't actually crabs!). Horseshoe SOS also includes a section that explains the many threats faced by horseshoe crabs as well as how our lives and the lives of one tiny shorebird, a red knot,literally depend on this ancient species. We've included a user friendly form to report tagged horseshoe crabs (dead or alive) or just tags found on beaches to the US Fish and Wildlife Service on the main navigation page. The US Fish and Wildlife Service needs this information, so please use the app to accurately report any tags you find wherever you may be in the US. Do your part to help one of our most ancient, amazing, threatened sea creatures.