* Attracting mates: The large claw is used to attract females during mating season. They wave it around, sometimes making a clicking sound, to show off their fitness and attract potential mates.
* Fighting rivals: The large claw is used to defend territory and fight off rival males. The larger the claw, the more successful the crab is in these fights.
* Defense: While the large claw is primarily used for fighting and mating, it can also be used as a defensive weapon against predators.
While the large claw looks intimidating, it's not actually very strong. It's more for show and display rather than crushing strength.