How to Attract a Mate - If You’re a Crab…
When it comes to courtship in crabs there are a few options out there. There is the classic pheromone approach (highly rated) as well as the show of claw strength and dexterity (bit cringe ngl).
This waving approach is mostly associated with Fiddler Crabs and we recommend asking benevolent auntie Google about it.
However there is another method, which requires the crab to internally grind, or stridulate, the ridges (striations) in its belly (gastric mill). To our knowledge, only Ghost Crabs are capable of making noise in this way but their efforts create a light rumbly-growling sound, which is guaranteed to get the attention of your partner!
Other stridulating crabs use external ridges on their bodies to create noises between 300 and 700 hz which are transferred through air and the ground to receptive would-be mates.
Try it now! If your internal organs aren’t blessed with hardened ridges then you’ve got until dinnertime to learn how to throat sing.
Rubbing striations is a key way that arthropods like crabs make noises, and the body structures to make it happen can be found in animals as diverse as crickets and flies.
In the case of crickets, it is usually the wings or legs that grind together. However the Pygmy Waterboatman stridulate their penises along their abdomen instead - lol. Despite only taking place over 50 micrometres, approximately the width of a human hair, this can create a sound of up to 99 decibels. Underwater this sound is roughly equivalent to a passing freight train, although much of that sound is lost when the sound waves hit air, though it is still audible if you happen to be on a romantic stroll through the country.
When it comes to crabs however, the best way to attract a mate is a combination of methods.
Smell good, look good, growl.
Easy.