Sawfish, also known as carpenter sharks, are of the ray’s family and characterized by a long, narrow, flattened rostrum, or nose extension, lined with sharp transverse teeth, arranged so as to resemble a saw.
A sawfish's snout is a long, flat blade that has about 20 teeth on either side. This snout may be used to catch fish, and also has electroreceptors to detect passing prey.
The "teeth" on the sawfish's snout are not true teeth, but modified scales. A sawfish's real teeth are located inside its mouth, which is on the fish's underside.
Sawfish are elasmobranchs - fish that have a skeleton made of cartilage, and a group that contains sharks, skates and rays. There are over 1,000 species of elasmobranchs. Sawfishes are in the family Pristidae, a word which comes from the Greek word for saw.
There is some debate over the number of sawfish species, especially since sawfish are relatively understudied. According to the World Register of Marine Species, there are 4 species of sawfish. The large tooth sawfish and the small tooth sawfish occur in the U.S.
Sawfish can reach lengths over 20 feet. The small tooth sawfish might be small in teeth size, but not in length. According to NOAA, the maximum length of a small tooth sawfish is 25 feet. Thegreen sawfish, which lives off Africa, Asia and Australia, can reach lengths of at least 24 feet.
Sawfish are found in shallow waters, often with muddy or sandy bottoms. They may also swim up rivers.
Sawfish eat fish and crustaceans, which they can find using the sensory capabilities of their saw, and which they can kill by slashing their saw back and forth. The saw may also be used to detect and dislodge prey on the ocean bottom
Reproduction occurs through internal fertilization. Sawfish are ovoviviparous, meaning their young is in eggs, but eggs develop inside the mother's body. The young are nourished by a yolk sac. Depending on the species, gestation may last from several months to a year. The pups are born with their saw fully developed, but it is sheathed and flexible to avoid injuring the mother at birth.
Their small intestines contain an internal partition shaped like a corkscrew, called a spiral valve, which increases the surface area available for food absorption. The eyes of the sawfish are underdeveloped due to their muddy habitats. The rostrum is the main sensory device.