Grouper "landlords" that carve out their rocky homes in the seafloor inadvertently give other marine animals free housing, a new study says.

Young red groupers, abundant along Florida's western coast, remove sand from hidden seabed holes. The resulting recesses act both as a habitat for the grouper and inviting homes for corals, lobsters, and other sea creatures.

The surprising find suggests that, like beavers, red groupers are "ecosystem engineers," modifying their environments to suit their needs while creating habitats for other animals.

(Related: "Predator Fish Help Coral Reefs Rebound, Study Shows.")

"The digging is phenomenal," said study leader Felicia Coleman, director of Florida State