Yes, the crab uses the barnacles as protection and sometimes camoflauge
they do this because they feel like it
Barnacles could be either gender, both boy or girl. A barnacle is not one gender.
Semibalanus balanoides is a common and widespread boreo-arctic species of acorn barnacle. It is common on rocks and other substrates in the intertidal zone of north-western Europe and both coasts of North America. The mean monthly temperature of the sea must drop below 45 degrees F for it to breed, so it cannot survive in shallow water.
barnacle
Inside a barnacle, you will find the animal itself, which has a hard outer shell made of calcium carbonate. The barnacle also has feathery legs called cirri that it uses to filter food from the water.
they are reptiles, reptiles can survive both water and land.
They need both air and water
Crocodiles and alligators are both amphibians meaning they can survive both in or out of water.
Barnacle
Box turtles need both land and water to survive.
amphibians can live in both water and land because their body can survive in both water and land. E.G- penguins