H is for ...
Today I will touch upon a strange creature that is commonly seen but often misunderstood. It is the hermit crab. Although its name has crab in it, it is only a distant relative of the family of crab. The hermit crab is more famous for its house hunting ability.
The hermit crab lives in a shell (Belonging to other sea creatures). This is due to its need to protect its long soft belly. If the shell is too big, the hermit crab will find it hard to move around or stay attach to the shell. If it is too small, the hermit crab is not able to retract fully into the shell. Moreover, its growth will be stunted.
The unique thing that the hermit crab do when they are house hunting is that they form queues when the shell they find is too large. This is quite logical as the hermit crab that will move into the vacant shell will leave its old and smaller shell behind which will allow the smaller hermit crabs a chance to move into the recently vacated shell.
There are also cases where the hermit crab has some pets that it wants to move to its new house. These pets are sea anemones that sting predators that may attack the hermit crab. In return, they get to feast on the leftovers of the hermit crab. The hermit crab will first check out its new shell. Once it is satisfied and moves into the new shell, it will then pry the sea anemones off its old shell and attach them to its new shell.
The question then arises about the need for the house hunting. Why does nature allow the hermit crab to survive if it has such a weakness? The truth is that it is a tradeoff that the hermit crab has evolved. All arthropods have an exoskeleton. In order to grow, they need to moult and grow a new exoskeleton. By investing in an exoskeleton with some soft parts, the hermit crab devotes the savings into house hunting for a protection to cover its soft underbelly (and cover its butt). This works well if there are available shells to move to which is why the coconut crab (relative of the hermit crab) is able to grow a full body exoskeleton once it reaches a certain size. The coconut crab is also the world's largest arthropod.
The hermit crab lives in a shell (Belonging to other sea creatures). This is due to its need to protect its long soft belly. If the shell is too big, the hermit crab will find it hard to move around or stay attach to the shell. If it is too small, the hermit crab is not able to retract fully into the shell. Moreover, its growth will be stunted.
The unique thing that the hermit crab do when they are house hunting is that they form queues when the shell they find is too large. This is quite logical as the hermit crab that will move into the vacant shell will leave its old and smaller shell behind which will allow the smaller hermit crabs a chance to move into the recently vacated shell.
There are also cases where the hermit crab has some pets that it wants to move to its new house. These pets are sea anemones that sting predators that may attack the hermit crab. In return, they get to feast on the leftovers of the hermit crab. The hermit crab will first check out its new shell. Once it is satisfied and moves into the new shell, it will then pry the sea anemones off its old shell and attach them to its new shell.
The question then arises about the need for the house hunting. Why does nature allow the hermit crab to survive if it has such a weakness? The truth is that it is a tradeoff that the hermit crab has evolved. All arthropods have an exoskeleton. In order to grow, they need to moult and grow a new exoskeleton. By investing in an exoskeleton with some soft parts, the hermit crab devotes the savings into house hunting for a protection to cover its soft underbelly (and cover its butt). This works well if there are available shells to move to which is why the coconut crab (relative of the hermit crab) is able to grow a full body exoskeleton once it reaches a certain size. The coconut crab is also the world's largest arthropod.
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