A team of scientists, led by Florida State University's Felicia Coleman, recently found that the red grouper off Florida's east and west coasts and throughout the Gulf of Mexico have created entire ocean communities by digging large holes in the sea's sandy bottom.

The researchers watched it work hard to remove sand from the sea floor, exposing hard rocks crucial to corals and sponges and the animals they shelter. In the same way beavers construct dams, red grouper excavate and maintain distinct holes whose rocky surfaces provide a place for coral, sponges and other marine life to congregate.

"Red grouper are the 'Frank Lloyd Wrights' of the sea floor," said University of California-Davis Professor Susan Williams, who collaborated with Coleman on an earlier, related study. "Its sea-floor associates include commercially valuable species such as vermilion snapper, black grouper and spiny lobsters. If the groupers are overfished, the suite of species that depends on them is likely to suffer."

Working along the West Florida Shelf, Coleman and colleagues observed the red grouper's excavating activities during both its juvenile stage in inshore waters and its adult stage at depths of 300 feet.

"We suspected that the groupers created the habitat," Coleman said. "We found through a series of experiments that they not only dug the holes but also maintained them by carrying mouthfuls of sediment from the center of the pit to the periphery and expelling them through their gills and mouths, then brushing off the rocks with their tail fins."