This inhabitant of the World Ocean stands out among others in that it has a jagged bone growth on its head, which really resembles a saw and makes up approximately a quarter of the total body length.
The exact biological name of this fish is the common sawfish, and it belongs to the stingray family. On the back of a sawfish (lat. Pristidae) there are two fins, and one on the tail, and unlike many other stingrays, it does not have a spine.
Just like sharks, the skin of sawfish is covered with placoid scales. Due to their great external similarity, sawnose rays are sometimes confused with sawnose sharks, but they are a completely different family of fish.
They can be distinguished by the way their gills are located: sawfish, like all rays, have gill slits at the bottom of the head, and sawnose sharks have gill slits on its sides. Besides, the fish drank It is significantly larger in size than sawnose sharks.
This species of fish is listed in the International Red Book and lives in the coastal part of the Atlantic, Indian and Pacific Oceans, as well as in the Mediterranean Sea. Sawfish, which live off the coast of the American continent, migrate from south to north in the summer, and from north to south in the fall.
The common sawfly does not lay eggs, but reproduces by ovoviviparity. One female Sawfish can give birth to fifteen to twenty babies at a time. Moreover, while they are still in the womb, their “saw” is completely covered with skin.
IN open ocean It is almost impossible to find a sawfish. For its habitat, it has chosen coastal areas, and sometimes it enters the shallows, and then you can see sticking out of the water dorsal fins.
It also happens that she comes into large rivers flowing into the ocean, and some of the sawfish species, for example, the Australian sawfish, have become so comfortable in fresh water, which lives in the rivers of the Green Continent permanently.
The diet of sawfish consists mainly of a variety of small animals that live in the sand and silt covering the bottom. It is for this, and not for any carpentry work, that a sawmill needs a saw. With its help, this type of stingray loosens the bottom soil and digs out those unfortunates from it, who then go into food.
However, there is also evidence that the saw blade can be used by the sawmill not only as a shovel, but also as a kind of saber. There is ample evidence of how these bottom fish quickly burst into schools of sardines or mullet and, like real fencers, hit their prey with a saw, which they calmly ate after it sank to the bottom. The sawfish became so famous thanks to its unusual appearance. Previously, there was even a legend that she was capable of sawing a wooden ship, and that is why even experienced “sea wolves” were afraid of meeting her. However, in fact, this fish is not at all dangerous for humans, and, like most other species of stingrays, when it encounters it, it often tries to quickly hide.
As for her commercial value, then it is very small, since the meat of the common sawfly is quite rough, although quite edible.
The largetooth sawfish (Pristis perotteti) is now firmly established in the inland waters of its habitat. For example, the population found in Lake Nicaragua appears to be entirely freshwater and may represent a distinct species distinct from sawfish rays found in waters along the coasts of Central America.
Like many sharks, sawfish rays produce litters of live young. The body of a pregnant female fish, caught off the coast of Sri Lanka, contained 23 fry. To make the process of pregnancy and childbirth less painful, the fry's teeth are covered with a protective shell, and the stigmas remain soft and flexible until the offspring are born.
The sawfish has a very impressive size, but up to gigantic freshwater stingray she still has a long way to go. The average length of her body is 4.5-4.8 meters. There are also larger individuals, 6-7 meters. It also weighs a lot - this is how a stingray 4.2 meters long was caught, the weight of which reached 315 kilograms. The heavyweight record belongs to a stingray weighing 2.4 tons. It's a pity that its length is not indicated anywhere.
These rays are born with a long but soft snout with small teeth hidden under a leathery shell so as not to damage the mother. In adult individuals, the length of the “saw” can reach 110-120 centimeters.
Unlike other species of stingrays, the sawfish does not have a spine on its caudal fin. Some people confuse these stingrays with sawnose sharks, which they closely resemble. How can you tell them apart? Everything is very simple. In sharks, the gills are located at the edges of the head, while in stingrays they are located at the bottom. In addition, the latter have a flattened body, the edges of the pectoral fins are fused with the head at the level of the mouth. All these features, as well as the absence of antennae on the snout, distinguish saw-nosed rays from saw-nosed sharks (Pristiophoridae).
Now we come to the answer to the question - why does a fish need a saw? It turns out that with its help, the stingray digs out small fish hidden from it from the silt and sand. In addition to the fact that the saw serves as a kind of “shovel” for him, it is also a formidable weapon. Having burst into a school of fish, the stingray furiously begins to swing the “saw” from side to side. After this, it calmly sinks to the bottom and swallows the wounded or “sawed” fish. This fish is completely safe for humans.
“I am a fish called saw -
I hope I get caught in the ocean!
And soon your schooner will be cut in half
It will fall apart under a sharp saw!”
Who doesn't remember this funny song from the cartoon "Blue Puppy"? You will be very surprised, but in fact the sawfish is not a fish at all. More precisely, not really a fish. It belongs to the family of saw-tailed rays from the class cartilaginous fish.
There are 7 numerous genera in the family, of which only 7 species of sawflies exist today - Asian, Queensland (or Australian), smalltooth, combed, Atlantic, European and green sawflies.
The sawfish has an elongated body, similar in shape to a shark. And on the head there is a long and flat outgrowth of its snout, a growth that is strongly reminiscent of a saw in shape (it has jagged teeth on both sides, resembling teeth), it reaches up to a quarter of the body length of the sawfish, which is approximately 1.2 meters in adult sawfishes, and tapers gradually from base to end.
The stingray has 4 lateral fins - two on each side, and 2 dorsal fins, in triangles. It does not have a spine on its caudal fin, like most stingrays. The skin of the sawfish is covered with the same placoid scales as those of sharks.
The tail part externally merges with the body, and some species have a caudal fin divided into 2 lobes. The skin color of the stingray is olive-gray with various shades different types, and the belly is almost white.
Sometimes sawnose rays are confused with sawnose sharks, but this is incorrect, although rays are the closest relatives of sharks. Unlike sharks, stingrays have gills located at the bottom, not on the sides. In addition, saw-tailed rays will be larger; their body length reaches up to in rare cases up to 7.6 meters, but smaller specimens are common - 4.5-4.8 meters; with this length, the stingray weighs about 300-325 kg.
The greatest weight that was recorded reached 2,400 kg, its length is unknown. The body of stingrays is flatter than that of sharks, and the edges of the pectoral lateral fins are fused to the head near oral cavity. In sawnose sharks, the body length rarely exceeds 1.5 meters, and the “saw” is less flat and thinner than that of sawfish.
If you look at the belly of a saw-nosed ray, a pair of gills and a mouth opening together look like a whiny face.
The sawfish lives in coastal waters all oceans except the Arctic, but in the open ocean it is almost impossible to find it. It often swims in such shallow water that its dorsal fins protrude above the water.
Five of the seven species live off the coast of Australia, and the Australian sawfish has become so accustomed to fresh water that it lives in rivers constantly, without swimming into the ocean.
Sometimes sawfly rays happen to swim into the mouths of large freshwater rivers - during seasonal migrations(summer and autumn). The sawfish, which lives off the coast of America, can travel quite far up the river. Sawfish generally feel excellent in any water - salty ocean, brackish and freshwater. But they cannot live in water contaminated with waste.
Sawfish rays are ovoviviparous fish (an already formed baby is born in the shell of a leathery egg) and can give birth to up to 20 babies, whose “saw” is soft at birth and hardens over time. In the womb, the baby's "saw" is completely hidden by the skin.
The standard diet of saw-tailed rays consists of bottom-dwelling invertebrate animals.
With their snout, using it as a shovel, it is very convenient for them to pick them out from the bottom of the sea. There is another way of hunting - to break into a school of small fish, wave your saw-snout in different directions, and then collect the crippled fish from the bottom.
It is generally accepted that sawfish are not dangerous to humans. However, several cases of attacks on humans have been recorded, some with fatal(there were several such cases in the Gulf of Panama). But, if the fish is not provoked or attacked, in the vast majority of cases it will not touch you.
On the contrary, she will try to hide when you approach. Just try not to step on it when walking in shallow water - stingrays love to bask in the sun, lying in shallow water on the sand.
In past centuries, there was even a legend that a sawfish could saw through an entire ship. In fact, her strength is not enough for such a destructive action. Don't touch the sawfly - and it won't touch you. And the song from the cartoon is just a figment of the imagination of its author.
The meat of the sawfly is coarse, but quite edible, but special nutritional value he has no idea. However, due to the pollution of coastal waters in some places, individual species Sawfish are on the verge of extinction and are listed in the Red Book.
Thus, we can say that a person represents much more danger for sawfishes, than vice versa. After all, this is precisely thanks to economic activity coastal waters are polluted by humans. And some peoples consider the saw of this fish valuable decoration your home and even weapons!
This is why the number of sawfish has sharply decreased, and only a few people on Earth can boast of having seen them alive.
The saw shark (sawnose shark) is one of the shark species best known for its sawfish. In the waters of Japan, Australia and South Africa there are about 8 various types sawnose sharks. Saw sharks live in temperate coastal waters, typically at depths of 40 meters (130 ft). These interesting creatures often killed because of them delicious meat. Sawnose shark numbers have declined over the past few decades due to commercial fishing, but they are still not listed as a threatened species.
Interesting Facts about saw shark
1. The saw shark has a unique snout.
This shark has a long, flat blade called a snout, which has approximately 20 teeth on both sides. This snout can be used to catch fish and also has electroreceptors to detect passing prey.
2. These teeth are not real teeth.
In fact, the “teeth” on a fish’s snout are not really teeth. These are modified setae or rostral teeth. This shark's real teeth are located inside its mouth, which is on the underside of the fish.
3. The saw shark is closely related to sharks and rays.
Sawnose sharks are elasmobranchs - these are fish whose skeleton consists of cartilage. They are part of a group that includes sharks and rays. There are more than 1,000 species of elasmobranchs. The sawnose shark is in the family Pristiophoridae, a word that comes from the Greek word for saw. NOAA's website refers to them as "modified stingrays with a shark-like body."
4. The saw shark can grow over 5 meters in length.
The saw shark can reach 5 meters in length and weigh up to 18.7 pounds. Females are slightly larger than males.
5. The saw shark is found in shallow waters.
Watch your feet! Saw sharks live in shallow waters, often with mud-like or sandy bottoms. They can also swim up rivers.
6. The saw shark eats fish and crustaceans.
Sawnose sharks eat fish and crustaceans that they locate using the sensory capabilities of their sawfish. They kill fish and crustaceans by cutting them with their saw. The sawfish can also be used to locate and hunt prey on the ocean floor.
7. Saw sharks are ovoviviparous.
Reproduction occurs through internal fertilization. Their young are in the eggs, but the eggs develop inside the mother's body. The young feed on the yolk sac. After several months of pregnancy, the eggs hatch inside the female body. The female can give birth to from 3 to 22 sharks (usually 10 sharks). Depending on the species, pregnancy can last from several months to a year. Baby sharks are born with the saw blade unfolded, but it is padded and elastic so as not to injure the mother at birth. They are born fully developed and look like a miniature version of adult sharks.
8. The saw shark population has decreased.
There appears to be no reliable data on saw shark populations, but NOAA estimates that shallow-water saw shark populations have declined by 95 percent or more, and large species There are even more saw sharks. Threats to sawnose sharks include fishing, fishing gear, and habitat loss due to development. The latter is especially true for young sharks that seek refuge in vegetation in shallow waters.
9. The body of the saw shark is covered with placoid scales (called dermal denticles) pointed towards the top. Saw sharks have yellowish-brown skin covered with dark spots. The coloration of the skin provides camouflage (saw sharks easily blend into sandy bottoms).
Photo. Whiskers on the snout of a saw shark
10. The saw shark has a pair of whiskers in the middle of its snout. They are used as a sensory organ that makes it easier to detect prey.
11. The shark has two dorsal fins, but no anal fin. They also have 5 or 6 pairs of gills (depending on the species) located on the side, behind the head.
12. Even though sharks and sawfish (sawfish rays) are similar in appearance, they differ in several aspects. Sawfish are larger, they do not have whiskers and their gills are located on the underside of the body (like stingrays).
13. Like other shark species, the saw shark uses an organ called the ampullae of Lorenzini, which contains electroreceptors to detect prey.
14. The shark uses its serrated snout to kill its prey. Rapid movement of the snout from side to side cuts the prey into small pieces, which can then be easily swallowed.
15. The saw shark is a carnivore (meat eater). Its diet consists of various types of fish, crustaceans and squid.
16. The saw shark can live as a solitary creature or be part of a group called a school.
17. Mating season for sawnose sharks occurs seasonally in coastal areas. Females mate once every two years.
18. The saw shark takes care of its young until they become sexually mature (at 2 years of age) and can fend for themselves.
19. Saw shark in wildlife can live more than 15 years.
Photo. Saw shark T-shirt
Saw shark attacks on people
Sawnose sharks are considered harmless to humans, but if you try to catch them or free them from a fishing net, they can cause serious injuries. Although their teeth do not contain poison, their wounds can ache and take a long time to heal. Sawnose sharks have never attacked people.
Some Marine life got their names due to their external resemblance to some objects, things or tools. For example, a fish is a saw: the photo shows that the head has a long, wide outgrowth, very similar to a double-sided saw (hacksaw), which is well known to skilled people.
Two groups of cartilaginous fish – sharks and rays – have this unusual “detail” on the front of the head. But the name “saw” was assigned specifically to saw-tailed rays, and this article contains information only about these fish. About sawnose sharks and detailed description how to distinguish them from saw-tailed rays.
Order Sawtooths
Among Cartilaginous fish there are two superorders, one of which is. It distinguishes groups - squads. The Sawtooth-like order is very original due to its elongated snout, which looks like an elongated rectangle with large sharp teeth along the perimeter. In this small group there is only one family called Sawfishes (Pristidae), known as sawfishes. There is only singular gender, including seven species.
Sawfish can be found in the subtropics and tropics of all oceans. Habitats for different species can be not only sea waters, but also fresh water bodies(for example, the Australian sawfly lives permanently in the river). Among them there are euryhaline species that thrive in both salt and fresh water. Thanks to this feature, these fish enter rivers from the sea, rising quite far upstream.
Appearance Features
The sawfish, the photo of which you see below, has a flattened body, but its shape is very similar to:
- the body is equally elongated;
- the tail is practically not separated from the body and is its continuation;
- there are two large high dorsal fins;
- in some species the caudal fin has two lobes;
- The skin is covered with placoid scales.
It is especially easy to confuse a sawnose ray with a sawnose shark. To prevent such confusion from happening, you need to pay attention to the abdominal part of his body. Here there are gill slits, which are located in two rows in front of each pectoral fin on the right and left. The slit-shaped mouth and two nostrils in front of it (often mistaken for eyes) are very similar to the "face". But the real eyes of the sawfish are located on the upper (dorsal) part of the body. They are small, and behind them there are sprays, thanks to which water is pumped through the gills, which allows the sawfish to remain at the bottom almost without moving.
These stingrays do not have a swim bladder, but serve to maintain buoyancy. rich in fat liver.
The pectoral fins are wide, wing-like. They have grown together and are playing important role when a stingray swims (making flaps). There is no anal fin. The dorsal side of the body is dark in color, and the ventral side is light. Saw-nosed rays belong to big fish and can reach more than 7 meters in length (European sawfly), and the smallest of them (Queensland sawfly) is only 1.4 meters. Now you have a good idea of what a sawfish looks like. Sawfish live up to 80 years.
“Saw” and its functions
The saw-tailed ray uses its unusual tool for two purposes:
- detect potential prey;
- and catch her (stun and immobilize).
A special feature of the structure of the “saw” (scientifically it is called “rostrum”) is the deep and strong fastening of its teeth in cartilage tissue rostrum. If one of the teeth breaks or is damaged, it will never grow again. Saw-nosed rays of different species have from 14 to 34 pairs of teeth. They all have the same size.
All sawfish rays are divided into two conditional groups: one has large saw teeth, and the second group has small teeth. The sawfly also has teeth in its mouth, but they are small in size.
Rostral teeth and protection from enemies
The rostral (located along the edges of the rostrum) teeth of the sawfish are not teeth, but modified placoid scales, found only in cartilaginous fish (the structure of such scales is actually a little similar to teeth).
The long rostrum, armed with sharp, strong “teeth,” is a powerful tool not only for obtaining food, but also for protection from enemies. Swinging this cutting and piercing tool from side to side, the saw-nosed stingray successfully defends itself.
His natural enemies there are sharks in the sea and aquatic mammals, in the rivers there are crocodiles. After all, some species (for example, the European sawfly) enter rivers and can remain there for a long time. Observations of stingrays kept in aquariums also indicate the use of the “saw” for protection.
Electroreception and prey search
We continue to get acquainted with the formidable “weapon” of the saw-tailed ray – its elongated rostrum-saw. On the surface of the “saw” there are numerous electroreceptors that help find food objects in muddy water, the same way they do it. Ampullae of Lorenzini (organs that capture electrical fields from animals) in large quantities are located on the upper surface of the rostrum. This makes it possible for the sawfish to receive information about living objects that float in higher layers of water above it and often become its prey.
Sawfish rays feed on small fish and various invertebrates that live in the ground.
With their flat saw, saw-tailed rays dig the ground to extract burrowing invertebrates, most often these are mollusks and crustaceans. Sometimes they use the saw as a saber. Bursting into a cluster of small fish (mullet or sardines), the stingray swings its weapon and hits the prey, which falls to the bottom. Having descended after the struck victims, the sawfly swallows them.
Lifestyle and biology
The predominant habitat of sawfish is shallow waters. The depth is sometimes so shallow that both high dorsal fins of the stingray lying at the bottom stick out above the surface of the water. Off the American coast, the saw-tailed ray is a migratory species and makes massive seasonal movements: in the summer from southern waters to the north, and in the fall they return to the south again.
All sawflies reproduce by ovoviviparity. Embryos develop in the mother's body, being in the egg and feeding only on the yolk, in contrast to, and, whose embryos receive part of their nutrition from the mother with the help of special education, vaguely similar to the placenta of mammals. On average, females of different species give birth to from 6 to 20 cubs.
The babies, while in the mother's body, already have a long snout, but it is soft, and its teeth are located under the skin. In newborns, the teeth of the “saw” are very small and reach their final length after birth.
Sawfish and man
There has been a commercial sawfish fishery for a long time. The rough meat of these stingrays is edible. But the fins, which are used to make soup, are of particular value. Liver fat is in demand traditional medicine. Of particular value is the unique rostrum, the cost of which reaches or exceeds $1,000.
The reason for the vulnerability of sawfish is their formidable weapon - a jagged “saw”, which often becomes entangled in the accumulation of debris floating in the water or in fishing nets. High damage The numbers of all species of this group of stingrays are affected by poaching. One of them (the Asian sawfly) due to overfishing and worsening environmental situation in the waters of the world's oceans International Union Nature Conservation has been assigned the status of "Endangered".
And in 2007, a ban was announced on the trade in body parts of all saw-tailed rays: these are fins, “saws” and their teeth, skin, meat and organs.
The sawfish is very similar to a shark, but it would be more correct to classify it as a family of sawfish rays that live in the tropical coastal waters of the Atlantic and Indo-Pacific regions. This stingray is easily recognized by the long bony outgrowth on its snout with many small jagged edges. A real saw. But why does he need it? What is he sawing her in his underwater world?
You will learn about this a little later. In addition to the waters of the three main oceans: Atlantic, Pacific and Indian, these stingrays can be found in coastal areas Mediterranean Sea, as well as off the coast of the American continent during the migration season. The sawfish thrives not only in sea water, but also in brackish and even fresh water, so it can often be seen in river mouths. Sometimes stingrays can be found at such a shallow depth that their large dorsal fins are visible above the surface of the water, cutting through the water surface.
The sawfish has a very impressive size, but it is still far from being a giant freshwater stingray. The average length of her body is 4.5-4.8 meters. There are also larger individuals, 6-7 meters. It also weighs a lot - this is how a stingray 4.2 meters long was caught, the weight of which reached 315 kilograms. The heavyweight record belongs to a stingray weighing 2.4 tons. It's a pity that its length is not indicated anywhere.
These rays are born with a long but soft snout with small teeth hidden under a leathery shell so as not to damage the mother. In adult individuals, the length of the “saw” can reach 110-120 centimeters.
"Saw" 
Unlike other species of stingrays, the sawfish does not have a spine on its caudal fin. Some people confuse these stingrays with sawnose sharks, which they closely resemble. How can you tell them apart? Everything is very simple. In sharks, the gills are located at the edges of the head, while in stingrays they are located at the bottom. In addition, the latter have a flattened body, the edges of the pectoral fins are fused with the head at the level of the mouth. All these features, as well as the absence of antennae on the snout, distinguish saw-nosed rays from saw-nosed sharks (Pristiophoridae).
Now we come to the answer to the question - why does a fish need a saw? It turns out that with its help, the stingray digs out small fish hidden from it from the silt and sand. In addition to the fact that the saw serves as a kind of “shovel” for him, it is also a formidable weapon. Having burst into a school of fish, the stingray furiously begins to swing the “saw” from side to side. After this, it calmly sinks to the bottom and swallows the wounded or “sawed” fish. This fish is completely safe for humans.
These fish are ovoviviparous, i.e. the female gives birth to already formed cubs, which are located in a leathery shell - the egg. A female can bring 15-20 cubs at a time.
As sad as it sounds, the sawfish is endangered and is listed in the International Red Book.
The "face" of a sawfish
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