That hermit crab is in that glass shell entirely by his own choice.. hermit crabs do not let you pick them up and ram them into a shell. Furthermore, this is obviously a terrestrial crab and almost certainly a pet. Put a shell-shaped object in front a crab and guess what they do? If it's big enough, 99% of the time they'll wedge their ass into it to find out how it fits, even if they don't plan on staying in it.
hermit crabs are picky
That hermit crab is in that glass shell entirely by his own choice.. hermit crabs do not let you pick them up and ram them into a shell. Furthermore, this is obviously a terrestrial crab and almost certainly a pet. Put a shell-shaped object in front a crab and guess what they do? If it's big enough, 99% of the time they'll wedge their ass into it to find out how it fits, even if they don't plan on staying in it.
It's just their nature.