Tropical waters are teeming with amazing creatures. One of them is a saw fish. Reaching a very impressive size with a frightening look, it has long been the object of legends and various fictions. For example, the fact that with its unusual growth on the head easily saws ships. Absolutely groundless fiction. Let's see in more detail.
It is an inhabitant of the coastal tropical waters of three oceans: the Atlantic, Pacific and Indian. In addition, it is sometimes encountered in the Mediterranean and off the coast of America. This is due to seasonal migrations. Sometimes swims in the mouths of rivers. In them, the fish-saw (photo) also feels quite comfortable, only it does not tolerate anthropogenic water pollution. Five of the seven species live in the waters of Australia, and one (Queensland) and completely adapted to life in a fresh environment, and in the ocean no longer swims. Pyloryl is a resident of shallow water, and very often you can see its body in clear water or determine its location by a fin above water, due to which it is often confused with a shark.
What does a saw fish eat?
Pyloryl is a predator, and quite dangerous. Lacking sharp teeth like a shark, he can severely maim his snout. There are two ways to get food. The first (predominant) - collecting small invertebrates from the bottom and from the sand. "Saw" allows the fish to break the ground, like a shovel, thus obtaining food. The second method is more aggressive. Breaking into flocks of fish (sardines, mullet), the slope begins to actively swing its "saw" in different directions for some time. Then it sinks to the bottom and collects crippled or rugged prey. For a human, the sawfish does not pose a danger, rather the opposite, but it is not worth purposefully angry.
Sawbird is an egg-breeding fish. This means that the egg develops in the body of the mother, and at birth the baby is as if enveloped in a dense shell. Nevertheless, it is already quite viable and independent. In the sawy slopes can be born up to twenty fry. "Saw" in young individuals is quite soft, strength and hardness is acquired only with time. When the young are in the womb, all the teeth are hidden by the skin and open only when they are born.
Piloshnuyu shark: what is the difference?
She, like the sawmill, belongs to the class of cartilage fish. However, she is a representative of another family, namely, the pony shark. The sawfish differs from it in the following external features (not to mention the anatomical differences):
- Dimensions. The first species is much larger, there were specimens with a length exceeding six meters, while the shark-bearing shark reaches 1.5 m at best.
- The location of the gill slits. So, at the sawmill, they are at the bottom, and at the shark on the sides.
- The shape of the fins. In the first type they are streamlined, smoothly passing into the lines of the body, and in the second - clearly pronounced,
- Differences are observed in the structure of the "saw" itself. In sawmill it is more accurate and even in width over the entire length, the same applies to the notches on it. In the shark, the outgrowth is narrowed, while it will be interesting to know that the teeth, if damaged, are capable of regeneration, while skates do not,
- By the nature of movement. The first one moves smoothly, undulatingly, the shark makes sharp movements, mainly with the help of the caudal fin.
It should be added that the sawfish is not commercial, although it is edible. When she gets online, she’s more likely to go to a trophy than to eat. And here at the pylon shark there is tasty meat and considered, for example, in Japan a delicacy.
Now this inhabitant of the ocean shoal is listed in the International Red Book, and the reason for this is man. With anthropogenic pollution of coastal waters, the sawlhead simply becomes a place to live.
How to recognize a pony shark?
From the outside, it is quite simple to distinguish sawn sharks from their distant relatives. Unlike stingrays, the Selah's gill slits are located on the sides of the body, and not on the belly. The pectoral fins are distinct and not fused with the body (as in skates).
Another striking feature - the "saw" of sharks is equipped with two long tendrils located approximately in the middle of the snout. The main purpose of this body is touch.
You can also note the significant difference between the two groups in size. Pilos sharks usually have a length of not more than 1.7 meters. As for the pylori rays, their sizes, as a rule, are much larger and can reach 7 meters or more.
Watch the video - Sawfish:
The pony sharks have two dorsal fins. There is no anal, as well as in a fairly close group of cat-like. Pectoral and pelvic fins well enough pronounced, paired, symmetrical. Body narrow, elongated. The back fin has an asymmetrical larger upper lobe.
Gill slits can be five or six. In accordance with this feature, pylon trees are combined into two different kinds.
Pony sharks are common in warm, mostly subtropical waters, inhabiting usually shallow depths of about 40-50 meters, but can also be found much deeper. Some individuals came across at a depth of about a kilometer.
Predators lead a bottom-dwelling lifestyle, eating predominantly crustaceans, mollusks, and small bottom fishes.
During the search for food used tactile tendrils, smell and electroreceptors. The latter, also called Lorenzini ampoules, help to capture the electrical impulses generated by the movements of the muscles of the fish.
Snout is used to strike at the victim. Also, with his help, you can loosen the sludge, taking food buried in it.
Species diversity of sharks
As already mentioned, pilonosy are divided into two genera, which combine 7 modern species. In this case, two types were described quite recently - in 2008.
Interestingly, the proper name of the "pilonosa shark" refers to the only representative of the genus Pliotrema (P. warreni), which differs from other relatives by the presence of six gill slits. So we can say that the general name of the whole family is its least typical representative.
The six-gab sawing shark is found only in one region of the globe - off the coast of South Africa and Madagascar. This is a fairly small view, having average sizes in the range of 80-110 cm, maximum - up to 1.7 meters.
It feeds on shrimps, small fish, squid and other mollusks. Lives mostly on the shelf at depths of several tens of meters (50-60 meters), but it was noticed and deeper - up to 500 meters.
This rare shark is caused very significant damage due to fishing by bottom trawls.
More widespread are representatives of the second kind - Pristiophorus. This includes all other currently known poniferous sharks (eight species). Their main and, in fact, the only difference from the six-taberniferous pilonos described above is the presence of five gill slits (like most other Selachians).
Sharks belonging to this genus inhabit the warm waters of all three oceans (except, of course, the Arctic Ocean).
Perhaps the most famous (and widespread) of all pony sharks is Japanese (Pristiophorus japonicus). This is a medium-sized bottom fish up to 1.35 meters. It is found at depths up to 500 meters off the coasts of Japan, China, Taiwan, and Korea, inhabiting the subtropical zone and part of the temperate.
Painted in sandy gray color. This most cold-resistant of all sawn-ups is an object of mass fishing. In Japan, popular kamaboko fish cakes are also prepared from its meat.
Several species of pony sharks are found off the coast of Australia. Cooler waters inhabit the Australian or short-nosed pony (Pristiophorus nudipinnis), as well as the long-nosed or southern (Pristiophorus cirratus).
These species measure up to 120 and 135 cm and are found at depths of up to 165 and 310 meters, respectively. More recently, in 2008, another representative of this genus was discovered, inhabiting Australian waters.
Unlike the previous two, this species is quite thermophilic and lives near the northern coast of the continent. In accordance with its distribution, it received the name of the tropical shark ponose (Pristiophorus delicatus).
This is a very small fish. The caught specimens had a maximum length of 85 cm (for females) and 63 cm (for males). The depth of the habitat is 250-400 meters.
Watch the video - Stony Shark:
Another species of sawn-fishes is found in the Atlantic Ocean, north of Cuba and east of Florida. This small fish, 80 cm long, is called the Bahamas shark-bearing shark (Pristiophorus schroederi). It is found at a fairly great depth - 400-1000 meters.
Studied rather poorly.
Little is known about the biology of most sawnbeams. It is likely that species that have not yet been described are found in the depths of tropical seas.
Pony-bearing sharks oviparous, bring in the litter about a dozen or one and a half young about 20-25 cm in size. Some species are significantly harmed by fishing, especially by bottom trawls. The meat is quite edible and quite tasty.
Want to know everything
This inhabitant of the oceans is distinguished, among other things, by the fact that it has a bone outgrowth with notches on its head, which really resembles a saw and accounts for about a quarter of the total body length.
The exact biological name of this fish is common pylori, and it belongs to the family of skates. On the back of the fish-saw (Latin. Pristidae) there are two fins, and one tail on the tail, and, unlike many other rays, it does not have a spike.
Just like sharks, the skin of a saw fish is covered with placoid scales. Due to the large external similarity of the sawn stingrays, they are sometimes confused with the pony sharks, but this is a completely different family of fish.
You can distinguish them by the way the gills are located: in sawfish, like in all rays, gill slits are at the bottom of the head, and in sawn sharks, on its sides. Besides, fish saw in size much larger than the 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. The sawlocks, which inhabit the shores of the Americas, migrate from south to north in the summer and from north to south in the fall.
Pylorus does not lay eggs, but multiplies by egg production. One female Sawfish can produce fifteen to twenty cubs at a time. At the same time, while they are still in the womb, their “saw” is completely covered with skin.
In the open ocean to meet the fish saw is almost impossible. For its habitat, she chose coastal areas, and sometimes goes to the shallows, and then you can watch the dorsal fins sticking out of the water.
It also happens that it enters large rivers that flow into the ocean, and some of the species of sawfish, for example, the Australian sawmill, are so comfortable with fresh water that they live permanently in the rivers of the Green Continent.
The diet of sawmills consists mainly of various small animals that live in sand and silt covering the bottom. It is for this, and not for some joinery, that the sawmill requires a saw. With its help, this kind of stingrays loosens the bottom soil and digs out those unfortunates, which then go for food.
However, there is also evidence that the saw can be used not only as a shovel, but also as a kind of saber. There are numerous evidences of how these bottom-dwelling fish rapidly broke into flocks of sardines or mullets and how real fencers struck their prey with a saw, which they quietly ate after it sank to the bottom. Previously, there was even a legend that she was able to saw a wooden vessel, and that is why even experienced "sea wolves" were afraid of meeting her. However, in fact, for humans, this fish is not dangerous at all, and, like most other types of stingrays, when meeting it, it often tries to escape quickly.
As for its commercial value, it is very small, since the meat of the common saw is rather coarse, although it is quite edible.
• Like many sharks, stingrays emit live litters. In the body of a pregnant female fish of this fish, caught off the coast of Sri Lanka, there were 23 fry. So that the process of pregnancy and childbirth is not so painful, the teeth of the fry are covered with a protective sheath, and the stigmas remain soft and flexible until the very posterity is released to the light.
The sawfish is quite impressive in size, but it is still far from the giant freshwater stingray. The average length of her body is 4.5-4.8 meters. There are individuals and more, in 6-7 meters. It also weighs a lot - this is how a slope of 4.2 meters long was caught, the weight of which reached 315 kilograms. The heavyweight record belongs to a ramp weighing 2.4 tons. It is a pity that its length is not indicated anywhere.
These stingrays are already born with a long but soft snout with small teeth hidden under the leathery skin so as not to damage the mother. In adults, the length of the "saw" can reach 110-120 centimeters.
Unlike other species of stingrays, the sawfish lacks a spike on the tail fin. Some people confuse these stingrays with the sharks of the pilonos, which they are very similar to. How to distinguish them? Everything is very simple. In sharks, the gills are located on the edges of the head, while in the skates they are located below. In addition, the latter have a flattened body, the edges of the pectoral fins are spliced with the head at the level of the mouth. All these signs, as well as the absence of antennae on the snout, distinguish sawn-headed rays from the saw-bearing 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 slope digs out small fish hidden from it from silt and sand. Besides the fact that the saw serves him as a kind of "shovel", it is also a formidable weapon. Bursting into a flock of fish, the ramp violently begins to swing the "saw" from side to side. After that, he calmly sinks to the bottom and swallows wounded or “sawn” fish. For humans, this fish is perfect safe.
Hexhaber plants are found not only among comb-toothed sharks. Pelonious selachians can also boast with one of their representatives - a six-wilted poniferous shark with six pairs of gill slits. As befits a shark, these slots are located behind the lateral surface of the head, in contrast to the stingrays, which have gill slits on the ventral side of the body.
The six-gill shark pilonos is found in the subtropical waters of the western Indian Ocean (capturing the waters of the Atlantic near South Africa), between southern latitudes at 23 and 37 degrees.
The species is very rare, some individuals were caught off the southern coast of Africa (Mozambique, South Africa) and the southern tip of Madagascar Island from a depth of 60 to 430 m. It is observed that adults prefer greater depths than juveniles.
Treats small species of sharks. The maximum size of a six-pointed pilonos caught is 135 cm, But it is believed that it can reach a length of 170 cm.
Normal dimensions do not exceed 100-120 cm in length.
The appearance of a six-wooded pilonos is typical for representatives of this detachment Selakh. A long streamlined body, ending at the tip of the snout with a bony sawtooth outgrowth, which is a continuation of the cranial rostrum.
Body color is brown or yellow-brown on the back, turning into a light, almost white on the ventral side.
Under the snout there is a pair of antennae. Six pairs of gill slits are located just behind the head. The teeth are small, the eyes are relatively large. Sprygals are located behind the eyes - an auxiliary respiratory organ, characteristic of benthic shark species.
Fins developed, especially the pectoral. Caudal fin heterocercal, anal absent.
The diet consists of small benthic invertebrates (crustaceans, shrimps, mollusks, worms, etc.) as well as fish.
The sawtooth outgrowth and the antennae of the pilonos help in the search for prey in the bottom soil and even to defeat it. With its instrument, the pylonus plows the ground and silt like a plow, and with side movements it can hurt or even kill prey.
Typical bottom predator. Prefers depths up to 450 m on the shelf or off the islands. When searching for food, it uses not only the senses, which are usual for all sharks, but also its unique sawtooth outgrowth. The touch received an additional instrument in the form of antennae.
Other details about lifestyle are not known.
Features of the structure and interesting properties of the body
The six-gable saw-shark is a unique representative of the squad, since it has six gill slits, and not five, like the rest of the pilonos. Such a number of gill slits have only certain types of comb-toothed sharks - six-gill and frijade. All other representatives of other detachments and families of Selachians have five gill slits.
A distinctive feature of all sawn sharks is, also, the absence of the anal fin, as in the cat-like.