Munida quadraspina, also known as the Squat Lobster are not lobsters at all, they are crabs. They can be found worldwide, there are more than 60 genera and almost 1000 species. Munida quadraspina is found in the Pacific Northwest waters. This is one in this photo.
They are small and colourful creatures that are always cool to see. They range in size from less than two and a half centimetres up to ten centimetres, depending upon the species. Squat lobsters come with ten legs. The first pair of legs are very long and contain claws. The first ones are quite small and used to clean the gills, the second set is long and is armed with claws. the three pairs of legs after that are used for walking.
These Crustaceans have a short abdomen that is folded under their body. Unlike lobsters and crayfish, squat lobsters don’t have the true appendages that form the tail fan that you will find on true lobsters. Squat lobsters are crabs, but they are not true crabs, and they aren’t lobsters either. They are in fact more closely related to hermit crabs than to lobsters
They are known to mate during their moult intermoult period. Unlike most other Crustaceans. Mating occurs when the females are ovigerous with very little or no moulting activity. Squat lobsters also displayed very short interbreed intervals or time between mating, generally not longer than a few days.
Squat lobsters are small creatures and are not harvested in most areas of the world. Sometimes they may be harvested and sold as cocktail shrimp and quite often used as poultry feed or as feed on fish farms. These creatures are quite fascinating to observe in the wild so keep your eyes open when walking our island’s beaches and you might just see one.