Sally Lightfoot crabs walk across a boulder as waves crash over the rocks in the background in the Glápagos Islands, Ecuador

sally lightfoot crab crab crabs glapagos galapagos islands sea ocean waves rocks shore shoreline tide wave spume grapsus grapsus water tidal pincer claw claws red crab coastal scavengers species wildlife darwin conservation ecology wild coast crabby scuttle creep crawl south america ecuador