Nepedia
Back to Discover
Advanced Reader
🧬

Sawshark

life science Maturity 5-7 Next article →

The sawshark is a unique member of the shark order Pristiophoriformes. These fish are defined by a specialized anatomical feature called a rostrum. This rostrum is a long, blade-like snout that resembles a saw. Along the edges of this rostrum, sawsharks possess sharp teeth. These teeth often alternate between large and small sizes. This tool allows the shark to slash and disable its prey.

Sketchbook of fishes - 25. (Longnose) Saw shark - William Buelow Gould, c1832
Sketchbook of fishes - 25. (Longnose) Saw shark - William Buelow Gould, c1832

To hunt effectively, sawsharks use a combination of sensory mechanisms. Halfway down the rostrum, they have a pair of long barbels. These barbels help the shark detect prey on the ocean floor. Additionally, the rostrum contains specialized sensory organs called ampullae of Lorenzini. These organs detect the electric fields given off by buried organisms. Once prey is located, the shark may use side-to-side swipes of the rostrum. This action can cripple small fish, squid, or crustaceans.

Pristiophorus nudipinnis McCoy
Pristiophorus nudipinnis McCoy

There are ten known species of sawsharks divided into two distinct genera. The genus Pristiophorus typically possesses five gill slits on each side. The genus Pliotrema is distinguished by having six gill slits. Examples of these species include the Japanese sawshark and the Bahamas sawshark. The Bahamas sawshark is known to live in very deep waters. It has been found at depths between 640 m and 915 m. Other species include the African dwarf sawshark, discovered in 2011.

Pristiophorus tumidens MNHN.F.SHA1593
Pristiophorus tumidens MNHN.F.SHA1593

Specific species show unique physical and behavioral traits. The longnose sawshark, or common sawshark, has the longest snout in its family. It can grow up to 44 cm in females and weigh 18.7 pounds. The shortnose sawshark has a broader rostrum and a more even brown color. It is often found in south-eastern Australian waters. The Warren's sixgill sawshark is another notable species from the Pliotrema genus. Females of this species reach about 136 cm, while males reach 112 cm.

Pristiophorus nudipinnis McCoy
Pristiophorus nudipinnis McCoy

Sawsharks have a fascinating reproductive process known as ovoviviparity. This means that the eggs hatch inside the mother's body. After a pregnancy lasting 12 months, the pups are born. A single litter may contain between 3 and 22 pups. These pups are born at a length of 30 cm. Interestingly, the rostral teeth of the pups are angled backwards while inside the mother. This prevents the teeth from harming the mother during development.

Pristiophorus nudipinnis McCoy
Pristiophorus nudipinnis McCoy

It is common to confuse sawsharks with sawfish, but they are very different. Sawfish are actually a type of ray rather than a shark. You can distinguish them by the placement of their gill slits. Sawsharks have gill slits located on the sides of their heads. Sawfish have gill slits positioned on their underside like other rays. Furthermore, sawfish have evenly sized teeth on their rostrum. Sawsharks maintain the characteristic alternating large and small teeth.

Sketchbook of fishes - 25. (Longnose) Saw shark - William Buelow Gould, c1832
Sketchbook of fishes - 25. (Longnose) Saw shark - William Buelow Gould, c1832

Many sawshark species live in deep or remote ocean environments. For example, the tropical sawshark lives at depths up to 405 m. The Japanese sawshark is often found at depths of 500 m. Because they inhabit such deep waters, humans do not interact with them often. Most species are currently listed on the IUCN Red List as either data deficient or of least concern. Scientists continue to study these animals to understand their life history. Their lifespan is thought to be 10 years or more.

Pristiophorus nudipinnis McCoy
Pristiophorus nudipinnis McCoy
538 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

🖼️ Images & Media (3)
File:Pristiophorus nudipinnis McCoy.jpg
Pristiophorus nudipinnis McCoy.jpg
File:Sketchbook of fishes - 25. (Longnose) Saw shark - William Buelow Gould, c1832.jpg
Sketchbook of fishes - 25. (Longnose) Saw...
File:Pristiophorus tumidens MNHN.F.SHA1593.png
Pristiophorus tumidens MNHN.F.SHA1593.png
More to explore

🔬 Go deeper

More advanced topics to explore

🪜 Step back

Simpler topics to build understanding

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.