Crab are nearly everywhere in the world. They can be found in marine, freshwater, and on land. Their exoskeletons are composed primarily of calcium carbonate and they’re armed with a single pair of claws. Most move along the bottom sideways, however, not all do. The sheer variety of crab is vast and dates back to prehistoric times. The earliest crab fossils date back from the Jurassic period. They are now believed to have two distinct lineages: one in the Old World and one in the New World.
Omnivores that primarily feed on algae, the species’ diets can consist of plankton, and for some primarily shellfish like clams, while others may even catch fish! Commercially important, they make up an estimated 20% of all marine crustaceans caught, farmed and consumed around the world.
Like with shrimp, there is a significant amount we know about crab, but there is a significant amount that we don’t know. With that, students and scientists who participated in BioAcoustic Workshops at University of Washington Friday Harbor Labs tagged and tracked kelp crab to learn more about their behavior in the Puget Sound. Here’s an example of tracking crab that students conducted during the bioacoustics workshop: