|Scientific name||Pristiophoriformes||Weight||15 to 20 lbs (6.8 to 9 kgs)|
|Pronunciation||saa shaark||Length||1.37 meters (4.5 feet)|
|Classification||Chondrichthyes, Pristiophoriformes, & Pristiophoridae||Location||Africa, Asia, & Australia|
The sawshark or saw shark is one of the most fascinating sharks present in the world’s oceans.
It often tops the list of odd-looking sea creatures due to its bizarre appearance characterized by a long serrated snout that looks a lot like a saw blade.
The shark’s jaw is lined with rows of sharp teeth on both sides, which it uses to slash at prey.
This sawshark is completely different from the sawfish.
While they both have a similar appearance (with slight differences), the sawfish is a type of ray, while the sawshark is a shark.
Despite the fearsome appearance of this shark, the sawshark is quite harmless to humans.
It lives deep in the ocean, so human interactions are quite rare.
In this article, you’ll learn all the interesting facts about this group of sharks, including where they live, how they reproduce, their current conservation status, and their significance to science.
Taxonomy and Classification
The name sawshark refers to any of the eight species of long-snouted sharks in the order Pristiophoriformes.
They’re further classified into the genus Pristiophorus and Pliotrema, differentiated by the number of gills they have.
The species within the sawshark order include:
- The common sawshark (Pristiophorus cirratus)
- Shortnose sawshark (Pristiophorus nudipinnis)
- Japanese sawshark (Pristiophorus japonicus)
- Bahamas sawshark (Pristiophorus schroederi)
- African dwarf sawshark (Pristiophorus nancyae)
- Lana’s sawshark (Pristiophorus lanae)
- Tropical sawshark (Pristiophorus delicatus)
- Sixgill sawshark (Pliotrema warreni)
The sawshark is a type of squalean shark (superorder Squalomorphii).
This means they’re distantly related to cow sharks, frilled sharks, lantern sharks, bramble sharks, and other related species.
The order Pristiophoriformes is a primitive group, with fossils of members of this order dating back to the Jurassic.
Sawsharks and sawfish look very similar in terms of their overall appearance, but they’re completely unrelated taxonomically.
The similarities in their appearance are a clear example of convergent evolution, where two distinct animal groups develop similar adaptations.
Sawsharks vary in size and general appearance based on the species.
They’re small to medium-sized sharks that grow to an average length of about 1.37 meters (4.5 feet).
Sawsharks have an elongated, slender body.
The shark’s weight can vary widely based on its size and species.
Female sawsharks tend to be larger than males on average.
Smaller sawsharks may weigh only a few pounds, while larger ones can reach 15–20 pounds or more.
Their most prominent feature is their long, flattened rostrum, which extends forward from the head.
The rostrum is lined with several sharp, tooth-like structures on both sides, giving it a saw-like appearance.
The length of the rostrum and the number of teeth may vary from one species to the other.
For instance, the longnose sawshark has between 19 and 25 teeth on each side of its rostrum.
The Japanese sawshark, on the other hand, has between 24 and 43 teeth.
The size of the snout teeth alternates between large and small.
Saw sharks also have a pair of barbels on their tapered snout.
The position of the barbels varies for the different species and is another way to recognize them.
For the common sawshark, the barbels are located closer to the snout tip than they are to the mouth.
The two genera of sawsharks are differentiated based on the number of gills they have.
Members of the Pristiophorus genus have gill slits on either side of their head.
The Pliotrema, on the other hand, are also known as the sixgill sawsharks because they have six pairs of gill slits.
The body of the sawshark is covered in dermal denticles.
These are small, tooth-like scales that help reduce drag and provide some protection.
They have two dorsal fins located toward the back of their body, as well as a caudal fin for swimming propulsion.
Like all sharks, the coloration of the sawsharks helps to camouflage them in their deep-sea habitats.
Color may vary slightly from one species to the other, but they’re typically yellowish-gray or brownish on their upper side, while the ventral (lower) side is usually lighter or white.
Habitat and Distribution
The different species of sawsharks are present in various locations worldwide, but they’re most commonly found in the waters of the Indian and Southern Pacific Oceans.
They’re typically found at depths of about 40 to 100 meters.
However, species that live in tropical waters are often found at lower depths.
The Bahamas sawshark, for instance, has been found in depths of up to 640 meters in the northwestern Caribbean.
The sixgill sawshark lives off the southern coast of South Africa and Madagascar.
The longnose and shortnose sawsharks are found in Australia, and their range sometimes overlaps.
The tropical sawshark is also found in Australia but is more common on the northeastern shores of the continent.
Species of sawsharks found in Asia include the Japanese sawshark and Lana’s sawshark.
Behavior and Social Structure
Sawsharks are carnivorous predators, and their specialized rostrum is thought to be their primary hunting tool.
Their active feeding periods can vary depending on various factors, such as water temperature and prey availability.
They are primarily nocturnal hunters, often foraging in the dark depths of the ocean at night.
During the day, they may rest or find shelter in underwater structures or in the sediment on the seafloor to avoid potential predators.
Sawsharks are generally solitary animals, which means they do not form long-term social bonds or live in groups.
But they’re not typically territorial species either.
They may have home ranges where they are more frequently encountered, but they do not exhibit territorial behaviors in the same way some other marine animals, like territorial reef fish, do.
Sawsharks remain within their home range and are not known for long-distance migrations like some other shark species.
However, they migrate vertically in the water column, moving to different depths based on factors like environmental conditions and food availability within their habitat.
Diet and Feeding
The diet of a sawshark typically consists of various marine organisms such as small fish, squid, and crustaceans.
However, different species have specific food preferences.
For instance, the longnose sawshark preys mainly on small crustaceans, while the southern sawshark or shortnose shark primarily feeds on fish.
Sixgill sawsharks have a more varied diet that may include squids, small fish, and crustaceans.
The extended rostrum and barbels of this shark are believed to serve an important function in hunting and killing prey, but their exact function is not well understood.
Experts think they use this serrated saw to cripple prey by swiping it from side to side when they encounter them.
The saw is also covered by a specialized sensory organ known as the ampullae of Lorenzini.
This organ helps to detect the electric field given off by prey swimming in the water or hiding in bottom sediments.
Sawsharks are patient hunters that rely on stealth and ambush tactics.
They swim slowly close to the seafloor, camouflaging themselves to get as close as possible to prey.
When they get close enough, they launch a quick and precise attack, stunning or injuring the prey with their rostrum before going in for the final kill.
Reproduction and Life Cycle
Sawshark mating occurs seasonally in coastal areas, but their exact mating season is unknown.
They also do not have any elaborate courtship rituals or displays.
Males and females typically come into contact with each other when they share the same habitat, and mating may occur if the female is receptive.
During mating, sawsharks use specialized claspers (modified pelvic fins) to transfer sperm into the female’s reproductive tract.
This process of internal fertilization ensures that the male’s genetic material fertilizes the female’s eggs.
Saw sharks have a long gestation period during which the embryos develop inside the female’s body.
The gestation period varies depending on the species and environmental factors, but it typically lasts up to 12 months.
During this time, the embryos receive nourishment from a yolk sac, not the mother.
This type of reproduction is known as ovoviviparity.
Sawsharks typically produce a relatively small number of offspring for every reproductive cycle.
The number of pups typically ranges from about one to 22, depending on the species.
This can vary based on factors such as the female’s size and age.
When the embryos are fully developed, they are born as live pups in shallow water.
The typical reproductive cycle of the sawshark is about two years.
The mother does not provide any further care to her offspring after birth.
The pups are relatively self-sufficient and are miniature versions of adult sawsharks, capable of hunting crustaceans and small fish in the water.
The exact lifespan of the sawsharks is unknown, but they’re believed to live for about 10 to 15 years on average.
Ecological Role and Interactions
Sawsharks are predators of various animals within their ecosystem.
Their specialized rostrum, sensory barbels, and hunting techniques make them efficient predators.
However, given their size, they are mid-level predators, meaning they only prey on small animals within their habitat, such as crustaceans and small fish.
They play an important role in regulating the population of these small prey species.
Sawsharks primarily live in benthic (seafloor) environments, feeding mainly on bottom-dwelling organisms and other small prey that swim close to their ecosystem.
This means they play an important role in regulating the population of bottom-dwelling animals and help to maintain the diversity and stability of this ecosystem.
Their feeding activities also make food available for scavengers or detritivorous animals that live on the seafloor.
Given its size, the sawshark itself may also fall prey to larger shark species and other big predators within its ecosystem.
Conservation Status and Threats
The conservation status of sawsharks is generally not a serious cause for concern.
Most of the sawshark species are classified as “Least Concern” on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species.
This is because their population is currently stable and not significantly threatened by various environmental and man-made factors.
However, some species, such as the Lana’s sawshark, are now listed as “Near Threatened.”
Many currently unlisted species may also be at risk, especially because of their low reproductive rates.
It’s important to note that the status of many sawshark species is uncertain due to limited knowledge about their population trend and distribution within their deep-sea habitats.
We do know that they’re threatened by climate change, pollution, and habitat destruction caused by various human activities.
Although they’re not targeted by commercial fisheries, sawsharks sometimes end up as accidental bycatch by commercial fishing operations targeting other species.
They may get entangled in deep sea fishing nets and trawls, which can lead to injury or death.
To help curb this, some countries have implemented various measures, such as modifying fishing gear and restrictions to protect known sawshark habitats.
Scientists are also actively researching to gather more data about sawshark populations, biology, and ecology.
The data gathered from these studies will be crucial for making informed decisions regarding the conservation and protection of the various sawshark species.
Unique Adaptations and Survival Strategies
The most distinctive adaptation of sawsharks is their elongated rostrum, which is lined with several sharp, tooth-like structures.
This rostrum is a multifunctional tool useful for hunting prey, as a defensive weapon, and as a sensory organ.
The sawshark uses its saw-like rostrum to slash from side to side to immobilize or injure prey.
It can also be used defensively when the shark is threatened by potential predators.
The rostrum is equipped with electroreceptors that can detect the weak electric fields generated by the muscles of prey.
This makes it easier for the sawsharks to locate hidden or buried prey, even in the complete darkness that characterizes their typical habitat.
Sawsharks have adapted a unique coloration that aids in camouflage in the benthic environment where they live.
The gray or brown color of their dorsal (upper) side helps them blend in with the seafloor when viewed from above, while the light color of the underside also camouflages when viewed from below.
This camouflage allows them to remain inconspicuous while lying in wait for prey and to avoid detection by potential predators.
Cultural Significance and Human Interactions
Saw sharks are recognizable due to their distinctive appearance, but actual encounters with humans are uncommon because of their deep-sea habitat.
Consequently, they do not pose a significant threat to people.
This fish is sometimes encountered as a bycatch in commercial fishing operations.
When incidental capture like this happens, the fish is either discarded or sold for their fins.
In regions where sawsharks are native, such as parts of Africa, Asia, and Australia, they can hold cultural significance for indigenous and coastal communities.
However, the fact that they’re rarely seen means there’s limited reference to them in local folklore, stories, or traditions.
People sometimes mistake sawsharks for sawfish due to the similarities in their overall appearance.
The only ways to tell these two cartilaginous fish apart are the presence of barbels on the sawshark’s snout and the position of their gill slits on the sides of their head instead of underneath the body.
Future Prospects and Research
Research relating to elusive deep-sea species like the sawshark is limited due to the challenging nature of their typical habitats.
However, a few researchers and scientists are studying some of these species to get some insights into their biology, ecology, and behavior.
Many of these studies are in the form of ecological research to better understand the deep-sea environment in general and the species that inhabit this unique ecosystem.
Also, with conservation efforts gaining momentum, researchers are working alongside conservation organizations to assess population trends and determine the exact conservation status of the different sawshark species.
This will make it easier to identify key threats and develop strategies aimed at protecting them.
Saw sharks are a unique family of odd-looking fish known for their elongated snout, which has a saw-like appearance.
The snout is lined with numerous teeth and is used as an important weapon for sensing prey in the water, hunting, and as a defensive weapon against predators.
Saw sharks are found in tropical and temperate waters in various locations worldwide.
They’re bottom-dwelling predators that mainly prey on crustaceans and other small bottom-dwelling animals.
While most species are not currently endangered, there’s still a need to actively learn more about these fish to identify potential threats that put them at risk and do our part to protect them.