The Sawfish, Pristis pectinatus, that occurs on the southeastern and Gulf coasts of the United States, has a snout elongated into a flat, blunt blade, on each side of which is a single row of twenty-four to thirty-two strong, sharp teeth.
This sawlike structure is about a third as long as the fish’s body and is a formidable weapon in even a small specimen. In the largest ones of twenty feet, it may be a foot wide at its base and six feet long, with teeth projecting well over two inches on either side.
The mouth of the sawfish is located on the underside of the head and is equipped only with small blunt teeth. It is the “saw” which is used to obtain food. With a nicely gauged sideswipe the sawfish impales a fish on one of the teeth, then swims to the bottom with it and there scrapes it off, quickly swimming over the fish to engulf it – before it can recover, should it not be completely incapacitated.
The “saw” may also be used in a more haphazard fashion, the sawfish swimming into a school of fish and rapidly striking from side to side. The dead or injured fish can then be devoured more or less at leisure. Sawfish have also been reported as rooting out crustaceans and other invertebrates with the “saw.”
Sawfish live in shallow, tropical, salt waters and the brackish ones around tidal inlets and river mouths. They also travel upstream into fresh water well beyond the region of tidal influence. They give birth to broods of as many as twenty young, which are born fully armed with a “saw”! At this time, however, it is soft and flexible and covered with a membranous sheath.
There are about six different kinds of sawfishes. Although they have a sharklike body, sawfishes are really rays, as can be seen by the location of their gill openings, which are underneath the head rather than on the sides, as in the sharks.