Until now, the only vertebrates known
to feed exclusively on sponges were two or three

teleost fishes. A new study hints that
the hawksbill, too, a marine turtle that lives

among tropical corals, may be a dedicated spongivore.
Intestines of Caribbean hawksbills show masses

of spicules, opal needles almost 5 millimeters
long, embedded in the epithelia.

No vertebrate diet of comparable silica
content has been described. Though well defended,