sea cucumber can harbor up to fifteen pearlfish at a time

Certain species of crabs and pearlfish take advantage of this rhythmic action and,once the sea cucumber anus is dilated,they shimmy in and take shelter.The rear end of a single sea cucumber can harbor up to fifteen pearlfish at a time.However, it seems that not all sea cucumbers put up with this intrusive behavior.Some species are equipped with five teeth around their anus,suggesting that they may have taken an evolutionary stand against unwanted guests.