I. Akimushkin. The march-strike of the 'red' fish. Light and vision. Archers and spearmen. The piranhas. Lungfish. Tailed amphibians. The giant salamander and the axolotl that 'plays in the water'. Fire-bellied toads, midwife toads and spadefoot toads. Parachutists. Just frogs. The other foreign relatives of toads. Sea snakes
There are times in a fish's life when it, to say it gently, loses its proverbial cool-bloodedness. And also its' appetite, caution, and, as people say it, common sense. Cautious pikes hang in the shallows, at the very edge of the coastal clutter. And there it is easy to stun them with a stick. The common bleaks can be caught by hand. Even the tiny paradise fish, ambassises, and other prisoners of the aquariums aggressively and bravely rebel against any intrusion into the 'territorial waters' that they consider to be theirs. Angrily they charge even at the kindly hands of their owner from which they usually got food. In desperate leaps from the water, they attack even the owner's face.
Can you guess when this happens?
When nature calls them out to reproduce. When, forgetting about everything, some fish seek, find and bravely defend a bunch of seaweed, a small space on the bottom or at the surface of the water - to each his own. It is an individual's territory. From here on it will be a protected place, guarded for the next generation and the piscine family, (for some fish species it is so).
Others, gathering into grandiose swarms, swim far from their home waters. (The time has come for the spawning migrations). The leave from the seas into the rivers. From rivers into the seas. The salmon demonstrate the first example. The second - by the river eels.
The North Atlantic salmon, the brown trout and their Pacific kin: the Coho salmon, the Chum salmon, the pink salmon, the sockeye salmon, the Chinook salmon and the masu salmon, annually, and - every species in its time - go from the seas of the Northern hemisphere into the rivers to lay their eggs at the source.
When a mighty instinct gathers all of the fish who need to breed to the mouths of the rivers, they swim there immediately. For some time the salmon swim here and there at the edge of fresh waters. Then, suddenly, all at once and in such 'great numbers' they go up the river that they literally fill it up. The water is swarming with fish. Some have the dorsal fins and the backs protruding above the water: the other salmon press them from below. And in places, where a shallow river narrows, the fish at the margins are pushed even to the shores by the pushing fish swarms in the center.
When the pink salmon swims up the rivers, it is the time of a great feast for foxes, bears, crows, lynxes and other beasts and birds that charge at the salmon and acquire them each in their own manner.
And the salmon hurry further and further upriver. Teams split from the main army and go into the side channels, they swim up the streams that are connected to the river, and they reach the very river sources. The fish via acrobatic jumps bypass waterfalls and rapids that now are met at every step. They often jump three m upwards and five forwards. Some fail: they fall after the desperate jumps not into the water behind the waterfall, but onto dry cliffs and rocks. Many die, but many safely 'land' and continue their journey.
In some Alaskan rivers, the Yukon, for example, the Chinook salmon go for 4000 km from the river mouths!
The Pacific species of salmon enter the flowing waters of the continents in summer, and every species - at its own time: the earliest of them all, in May, the Chinook salmon storms the rivers, the tastiest of them all. The Americans call it the royal salmon, and the Japanese - the prince of salmon. Then go the sockeye, the muso, the pink, the Chum, and only at the end of August-September - the Coho. As soon as they arrive at the spawning grounds, the fish spawn.
The Atlantic salmon spawns in autumn and winter, and not immediately after it enters the fresh water.
'In general the salmon biology is incredibly complex: in each river its' life is unique' (the aca-demian L. S. Berg).
The Atlantic salmon, just like the wheat, has two forms, the summer and the winter. And the similarity is not just in the names. The winter sorts of wheat, to continue growing, must winter be-neath the snow. Only after the cold 'treats' their cells in mysterious ways, they begin to fruit in the next summer. Ditto the salmon: the winter sorts must, to ripen its eggs and sperm, to winter under the ice in cold river water. The summer sorts do not need that.
The Atlantic salmon enter the rivers several times a year. In spring, as soon the rivers are free of ice, the 'ice salmon' appear. These are large females with underdeveloped eggs. Probably they have gathered since the last autumn in the mouths of rivers and wintered there.
In July, the rivers are besieges from small, about one-two kg in weight, salmon that are mostly males. These are young fish that hurry to bring their offspring into the world. They just spent one year in the sea, as soon as they reached one year in age - and they are already back in the rivers to reproduce. Other salmon live longer in the sea, for two-three years, without spawning.
Finally, from the end of August and until the frosts, arrive the 'autumn' salmon - almost all of them are large females without mature eggs.
Now, the salmon that left the seas in summer spawn in that same year, in winter. And the 'autumn' is the winter breed: only after a year, in the next autumn and winter, will it spawn.
As soon as the salmon enter the rivers, from the gluttonous carnivores they became the fasting yogi. While they live in rivers, they eat nothing. Stores of fat accumulated back in the sea support their strength. They do not have time to eat and they have nowhere to 'store' the food: the sexual organs of the fish grew so much that they push out the sides and squeeze shut the intestines. The coloring changed: it is not silvery as it was in the sea, but dark. In case of the Atlantic salmon - with red spots on the sides. And there grew a hump on the back, it is especially tall in the male pink salmon. Plus, the males' jaws distorted like pincers, as the crossbills' bills.
The salmon spawn in quick-flowing streams with transparent water and rocky bottoms. To reach them they often go to the very sources. They spawn in such shallows that the fish have to lie on their side - only then does the water cover them completely. Each fish goes only where, in that same river and even that same stream, where it itself was born several years ago.
The males jealously guard their females, chase away the other males. Before laying its' eggs, a female clears the designated spot from garbage, silt, and waterweeds. It lies on the side and slams the tail: silt goes upwards, revealing sand beneath it. Then the female digs a pretty deep pit in the sand - 2-3 m long. There it lays several thousand eggs. With tail strikes, it covers the pit with sand and pebbles. It makes several such nests. The work takes two or three days, sometimes a week.
Then the female salmon guards the next. It stays, awaiting death, at the cradle of the new life. May female salmon perish at the nests from exhaustion. Many males also die in that same river. Exhausted, mauled, sick, they feebly swim down the current; the waters carry some quickly, backwards and upside down.
'Many tribes of the Pacific salmon are worth noting that they are born and die rivers, but mature in seas and only once in their lives they spawn and mate' (S. P. Krasheninnikov).
That is so with the Pacific salmon. But some European specimens of the Atlantic salmon return to the sea alive and well from their hard trips to 'the promised waters'. In sea they recover, greedily devouring herring and lesser sand eels, recover, fatten, and by the next year they are ready to travel again.
No more than one quarter of all European salmon, and sometimes only 2-4 percent return to spawn a second time. Very few return to the rivers thrice. And in Scotland, an old female was caught. Thirteen annual rings were counted in its scales: ergo, the fish is 13 years old. No salmon older than her was caught. They continued to investigate further and discovered that the venerable salmon has visited Scotland four times already and came to spawn a fifth time. It is a record.
In spring, the young Pacific salmon usually go into the sea (only the young sockeye live in rivers for 1 to 3 years). But the young Atlantic salmon do not hurry to visit Neptune. One, three, five years they grow in rivers and then all at once, in masse, abandon them. And it happens that in places where only yesterday from any rock, you could see their happy swarms, today you will not meet a single young salmon.
But not all of them leave: some males remain in rivers. Why? This exception from the rules have a big biological meaning. The thing is that the male Atlantic salmon die quicker than the females do. They almost never return to the rivers a second time, thus sometimes there are not enough males on the spawning grounds. To compensate this loss, some young male salmon remain in the rivers. In fresh water, they grow poorly, but sexually mature quickly and are always ready, if the big males are not around, to fertilize the eggs of a female that returned from the sea. These dwarf homebody males develop from the same eggs as the other salmon do.
The Ladoga and Onega lakes have salmon (female and male) that also do not leave for the sea. Big lakes replaced the sea for them: annually, at the appropriate time, they go to spawn into the nearby rivers and then return to the lakes anew, thus reproducing the entire migratory cycle of their species in miniature.
The brown trout too stays permanently in some montane rivers and lakes. Thus, the famous trout is a special breed of the brown trout. The brown trout is a salmon, closely related to the Atlantic salmon and spawning in the same rivers that the European specimens of the Atlantic salmon do. Also, the brown trout lives in the Black, the Azov, the Caspian and the Aral seas.
The Wyg River empties into the White Sea. Once, in this river, an Atlantic salmon was caught with a Norwegian mark 'June 10, 1935'. The soviet anglers caught it two months later! The Atlantic salmon in question was a female and hurried to spawn up the Wyg, where it was born six years ago. Who could imagine that the Atlantic salmon leaves the mouths of its native rivers so far behind! For from the western coast of Norway, where it was caught for the first time, it had swam two and a half thousand km. It covered the same distance on the way back, but now it was in a great hurry: for the Norwegians had delayed it with their marking procedure. Daily the fish had swam on the average around 50 km!
In its journey, the salmon saw hundreds of rivers quite suitable for spawning, but the fish sought out the one where it was born a fry. It swam continuously in a straight line, in a well-known route - otherwise, if it knew the route poorly, it would have wasted much more time for its' heroic raid. For 50 km daily is a great speed for the salmon. (The record is 100 km daily).
On Kamchatka, when salted fish was loaded, a marked Chum salmon was found. It was marked on the Unga Island, near Alaska, and it was caught on the other side of the ocean in about a month. A pink salmon, marked in Korea, swam more than 1600 km in 2 months and was caught by people once more in the Amur bay.
An insatiable appetite sends the salmon from one end of the sea to the other. Chasing swarms of herring, they do not refuse the other fish that they can swallow. In the sea, the salmon grow six times faster than they do in the river.
At the end of a second year living in the sea an Atlantic salmon weighs already around 5, and by the end of a third - more than 8 kg.
Only a few Atlantic salmon feed for 4 years in the sea. Usually, not spending even half of that time, they return into rivers for their first spawning. And as we already know, some spend in the sea even half of that time. Ditto for the pink salmon: it is a fast-growing member of all the salmon species.
An Atlantic salmon that is especially lucky in life grows up to 1.5 m in length and weighs 40 kg.
It was decided to check: the salmon are born with the knowledge of their native shores or the fish acquire it after they hatch and live in a river for some time?
People transported the salmon eggs from the streams, where they were laid, into other rivers. When the fry hatched, they were for some time fed in special nurseries. Then the young salmon were marked and released into rivers alien for them.
And what happened? After several years having swam in the sea, the salmon returned to the rivers where they had lived as youngsters, and not where their parents laid them. Thus, the knowledge of the spawning grounds is not an inborn one. It acquires during the first years of life and retains in memory for at least 2 to 4 years while a salmon lives in a sea.
What marks does the fish remember? Chemical ones, apparently: it remembers the smell of home, the taste of the river water where it lived its' youth.
Experiments shown that many fish have simply a phenomenal memory when it comes to smells! And a very fine sense of smell too. A gudgeon, for example, is 250 times more sensitive to the smell of rose oil and 512 times to the sugar dissolved in water than a human is. It also distinguishes the water of one river from another.
When salmon had their nostrils clogged and released into the sea, they could not as precisely as before remember their native rivers. They swam mainly by guessing. Thus, the sense of smell, when it comes to searching for the path, play a very important role, but not a unique one, since it doesn't solve the entire problem. For, when going into the sea, the salmon swim truly far away from the river mouths to which they return afterwards. So far that no smell of home can help when they begin to go back.
What helps them then? Nobody knows. Maybe the sun and the stars serve as guides...
LIGHT AND VISION
Not everyone clearly visualizes a sloth, or, say, an orangutan, even though we share an element with them, but it is hard to find anyone who had not seen a fish. For it is easy to see them - just enter a... food store. Fish - are our food and this role of theirs, according to oracles, will increasingly grow in the future.
What variety of forms! Prototypes of torpedoes, missiles, arrows, cannonballs and throwing discuses supremely easily pierce the watery depths, making unimaginable trajectories in them. More-over, this does not even look like a fish: a snake! Yes, it is an eel. In addition, this monster, luxuriating in the soft silt, impressively forewarns various sluggards: it lay for so long that it became completely flat. Even its eyes have moved completely onto one side! Animated figurines of knights from the chessboard of Neptune himself... Fish that can be much more easily be taken for knots of barbed wired... Fish, armed with surgical instruments, swords, or just idyllic fishing rods; fish that are almost truly winged... In short, the variety seems endless!
Moreover, all of them glow and shimmer with such a multitude of color that one begins to think biologically blasphemous thoughts: all of this great coloration is not for disguise and not for intimidation - but for beauty!
Fish great and small... The legends speak: the curious Alexander of Macedon descended to the bottom of the sea in a glass vessel and saw on the seafloor such an immense fish that it took three days to swim by. William Bib, and after him - many more Russian and foreign explorers of the depths, did not discover such a fish. However, there are fish seven meters long.
In addition, the smallest fish, according to the scientists, is the pandaka of the Philippines. It is literally a fish big enough for a single tooth: seven mm long. For a while, fashionistas carried these fish in... their years. In crystal aquariums of earrings!
Simple or fancy, sweet or scary, big or small - all of them are pretenders to the roles of our ancestors, and it is hard for us to refute this relationship: when we are embryos, we too have gill slits...
Just as we do, the fish see, hear, smell, although it must be pointed out that some of the fish are eyeless or hard of hearing.
However, the life of a suppressing majority is equipped with a color vision. If among the mammals only a few possess color vision, then among the fish it is common.
In the past, to catch sardines, an Italian angler would store... logs. At night the barge, setting a huge fire at its back, the light of which would pierce the water for thirty meters in diameter, would go out to see.
It was a majestic sight, and the fish would appreciate it first: soon a swarm of sardines would begin to gather, pushing closer to the light. Then the barge would take the course back home and the fish, mesmerized by the sight of flame, would go with it. Having reached the coastal shallows, the original fire would be put out, and in its place, another fire would be lit on shore that was just as bright. The confused fish would swim to it, and the normally cautious sardines would not sense how a net surrounded them...
Once, on the shore of the Drevyato lake, (located in the former Kovenskaya district), appeared a red-sided traction engine with a dynamo-machine and a big electric lamp that was designed to be lowered into the water. 'It won't work', -- said the skeptics from the nearby villages and were proven right. Just not fully. When, having chosen a darker night, the unusual anglers did a first cast of the glowing fishing rod; a cloud of fish filled the glowing space. Sadly, the fish there were not to the commercial standards: much too small. 'But where are the zanders?' - the inventors wondered.
However, the zanders did not appear, no matter how deep the equipment was lowered...
They could not appear. The reticulum of a zander is shining, rich in guanine - a substance that while reflecting even the weakest light, makes the eyes of this fish into the most sensitive equipment. The distant light of the stars is enough for this predator to see excellently in the dark; a strong light simply scares the zander, and naturally, this fish hurries to leave such an unpleasant place.
As for the small fish that swam to the light of the Drevyato's experimentators, they, just as sardines, and the multitudes of other so-called daytime fishes, have differently designed eyes: their reticulum is strongly pigmented with melanin - a substance that consumes light.
The light of a false dawn gathers these fish, calls them to an active lifestyle, they swim to it, and end up, de-facto, in a tight sack.
Light attracts sprats, trachurus, European anchovies, Atlantic mackerels, salmons... The European anchovies, gathered in the light pillar of a projector, are sucked in via a specially designed fish pump.
The Pacific saury is caught with somewhat greater difficulty. At first, the ship sails at night, seeking this fish, scanning the sea with a projector. If they find this fish, it is seen immediately: this species, crazed by the sudden light, jumps out of the water.
Here, the captain of the fishing boat gives the order 'stop!', and the crazed fish is pacified with a blue light. Having pacified the Pacific saury in such a manner, that it is too early to grow active, the morning has only broken, this fish, collected into a compact swarm near the vessel, compact even more, lighting-up the red projector. Then it is enveloped in a net from below and pulled out of the water.
Even simpler is the method to catch salmon, invented by the Norwegians. They paint coastal cliffs white, and put the net between them and the water. Confused, the fish in question swim to the lighter colors and are entrapped and caught.
Sadly, to catch fish that fear the light (lamprey, tuna, Atlantic bonito, eel - and there are much more species), the electricity had not brought an equally significant breakthrough.
Although, when it comes to eels, back in 1905 a certain Petersen from Norway offered a very witty electricity-based means to catch these fish: in the shallows, where it is easy to catch fish - fish traps, and around, on a wide area - hundreds, maybe even thousands, of lamps. The eels that would hide there would not endure the light pressure; they would swim into the darkness and be caught in traps. Sadly, it is unknown if this method was tested. In any case, the eel remains one of the hardest to catch fish.
Before the revolution, a way to catch lamprey on Volga in winter 'via the lamp' was known. Where the current was fast, a hole was cut in ice; next to it, a light source was put. Lower down-stream more holes and around them were people, armed with nets. The lampreys, swimming past the illuminated spot would be scared, and carried by the current, ended in nets.
As a rule, fish fry hurries to light. That is understandable. They feed on plankton, and plankton is where the light is! As they grow, some of them change habits.
The global ocean devours light with a crazy appetite. It has been calculated: if the sun is in the zenith, and the sea is smooth, 98% of energy of the direct sunrays that touch the surface will be consumed by water. This quantity, of course, diminishes as the sun goes down, but the sky with a mass of scattered light remains above the sea. That light gets consumed as well.
Three quarters of our planet is taken by the global ocean. This giant consumes so much light that so far no computer can express it in numerical digits. A big part of the rays' energy goes to heat the water. The rest tries to brighten the gloomy kingdom of Neptune.
Sadko, a rich guest, apparently stayed in the shallows, (no more than five meters deep); other-wise, he would not have seen many colors. After the indicated mark, green and blue ones replace the whitish-yellow tones, common to our vision... It grows ever darker...
Even somewhere with virginally clear water of the ocean, the brightness of light during diving diminishes ten times at every fifty meters. In about four hundred meters away from the surface, the sun is powerless...
However, the depths glimmer with ghostly lights. Here, the animate, (and there are info, that the inanimate as well), themselves provide the illumination. Various small critters shine as bright dots. Here even the squid, showing the well-known trick with its double, casts from its' siphon not an ink clone, but a bright, colorful one.
Moreover, here the fish too glow in the dark. Some have basic lamps, built-in for convenience into one or another body part. The others shine as if they are encrusted with gems. There are even such that glow completely, resembling the negative images on a black-and-white photo film.
Falling into the water, the ordinary sunlight immediately, if one can put it so, stops being itself. Water is a giant light filter, or, more correctly, a most complex combination of filters that break-up the light in the most confusing, and on occasion in the most bizarre manner.
A person, who descended for the first time onto the depth of fifty meters and wounded a finger there, will see something green leaking from him. This is how blood looks in the water.
A gloomy kingdom. Dim shades or darkness. Nothing rejoices the eye. And only if into that world, where its' inhabitants move like ghosts, the strong light of a projector will cut in, then everything will play with bright colours - a palate of an artist who loves the local colors!
You will involuntarily think: what beauty is wasted! In addition, what for it is for the inhabitants of the gloomy world, if it is not seen?
However, who knows, maybe they see more than we suppose...
Experiments have permitted to establish: an ordinary small Crucian carp that lives in a peat mine in Shatura can see a mosquito larva with one in twenty-milliard share of daylight. We, in the same circumstances, will not see an elephant.
Various waters, various depths, very varying eyes...
Nice nearsighted eyes, opened wide as if in surprise. An angler on the tall shore of the Oka River can be calm: the large zanders, pikes and burbots that swim in fore waters almost cannot see him - for them everything is murky in the direction of land. A pike, for example, is famous for its sharp eyes, and it sees its' prey only from two - two and a half meters.
The fish eyes are not above various optical enhancements. In the fresh waters of Central and northern South America swims an amusing four-eyed fish. It remains in the water, as it is supposed to, but the eyes are half above the surface. They are divided into two cameras: the top ones, (with a flatter eyeball) watch in the air, the bottom ones look into the water.
The eyes of the deep-water kin of our ordinary salmon are just as good (the barreleye family, order Argentiniformes). The Bathylychnops, the biggest (up to 50 cm) of them all, has two eyeballs in each eye. One of them, which is bigger, sees what is above, and the second one looks below and to the side. Now there is a fish that if it gets curious, does not need to whirl its head around: it is already provided with an all-around vision. Other barreleyes have telescopic eyes. They are elongated upwards in cylindrical shapes, their field of view is narrow and therefore - binocular.
The Scopelarchidae fish (deep-water fish from the same order) overpower the surrounding dark-ness in a genius way. Spots of pearl color glow at the bases of their telescopic eyes. They light their path with literally shining eyes.
Yet it must be admitted that such wonderfully original fish are not that numerous in the underwater world. An overwhelming majority must use eyes of ordinary shape, albeit equipped with internal mechanisms of surprisingly fast and accurate pinpointing the prey. Something just has to flash by - and the fish immediately grabs it. The moving muscles of its body execute without mistakes the leading orders of the eyes (currently, physiologists are successfully studying these excellent abilities of them).
'The most surprising is that this inborn reaction, known under the name of the 'aiming reflex' is observed in the majority of fish as soon as they hatch from their eggs. Apparently, its' mechanism is encoded in the genes and is in the brain of newly born fry practically 'ready'.' (B.V. Loginov, A.I. Gabov).
It is necessary to distinguish the form in details - whether it is a predator or prey. The fish do so. The pike and perch, charging at a fishing lure that the angler has chosen to be the one from a magnificent set - is this not the proof! Moreover, this truth became persuasive after lab studies. It was proven that fish learn and remember various geometric figures and it is not easy to trick them in this field. For example, the aquarium goldfish can distinguish between the two circles who differ in diameters by only three mm. In addition, the famous sticklebacks recognize a familiar object even if an unfamiliar side is turned towards them.
The thymallus, an eager hunter of fast-flowing rivers, if you get the chance to watch it for a long-er period of time, will surprise you at first by precise strikes after various prey items located on the surface of water, and then, if it will start to drizzle, it will disappoint you with shameful misses. The rain ruined the perspective, hence the cause of misfires.
However, the rains have went for a week... Knowing, that now it is in vain to catch via lure (a fake bait swimming in the water with a hook inside), the thymallus will hopelessly miss, anglers stay at home. On the seventh day of rain some arrival, dismissing everything, puts on a raincoat and, followed by mockeries, goes to fish. However, the jokers are wrong! In the evening, the angler returns with a rich catch. It seems that the thymallus is caught just fine! Now, of course, everyone decide to go fishing tomorrow, regardless of rain, plus by the next morning the rain is over too, and the sun is shining. Everybody casts his or her fishing rods, but... the thymallus misses!
In addition, it is understandable. Having grown hungry in the bad weather, the thymallus learned to adjust to the rain in their strikes, and when the bad weather ended, they could not immediately readjust.
Can you imagine, they too have optical illusions...
ARCHERS AND SPEARMEN
The archerfish were kept in aquariums for a long time, but not everything is still clear in their biology and even the 'technique' of archery.
How they are shooting was seen by many, but the composition of their 'cannon' was described only in 1926. However, until recently, all sorts of tales regarding the behavior of the fish before the shooting were found in literature.
The ichthyologist K. Lulling from Western Germany, in his monograph 'Archerfish', written in 1955, described in details the conditions, necessary to keep them in the aquarium, their diseases and their treatment, the histological anatomy of the eye and the behavior of the fish during the shoot. In general, from his work and from the works of others, the following was established.
The elongated indent on the roof of the archerfish's mouth, when the fish presses its meaty tongue onto it, turns into a sort of small-caliber rifle barrel. Before the shot, the archerfish fills its mouth with water. Then squeezing hard its gill-lids, the fish pushes the water out of its rifle-mouth. The dexterous tip of the tongue, rising and falling acts as a valve, and depending on its position the archerfish fires a thin stream of water or a series of droplets. At the same time, it keeps the tip of its muzzle underwater.
After selecting its target, the archerfish carefully stalks it, trying to be as close to its goal as possible, and trying to come upon the 'firing position' directly beneath the target. The last is understandable: the rays of light, falling vertically, are less distorted in the water, and the sniper fish has an easier time to correct the refractionary distortions.
Sometimes, while aiming, it moves slightly forwards or backwards. Then, after turning to a certain angle to the vertical line, the fish tries to position the goal to a similar direction away from both eyes in conjunction with the trajectory of flight of the water 'bullets'. If there is a miss, which happens rarely, then the second shot is more correct: the archerfish, so to say, figured the problem out!
After several shooting exercises the archerfish loses interest in that affair. Food, gained with the 'archery' is not the most important part in its menu; it is often sated by what it finds on the surface of the water, on its bottom, among the aquatic plants. But if it is hungry, then it 'shoots' at everything that however slightly reminds the fish of a desirable prey - an eye of a human which close to the water's surface, a lit cigarette. The Malayans are using the shooting enthusiasm of the hungry archerfish for a long time now.
In Indonesia, the archerfish are taught various tricks, and then competitions are held. The trained archerfish show-off their art during those times. For example, they extinguish lit matches and candles with successful hits. Not only the accuracy, but also the distance of the shot is taken into account. The most 'long-reaching' fish supposedly shoot up to 4-5 m. The most accurate distance is 1-2 m.
The 4-6 species of the archerfish family (the Perciform order) dwell in brackish and marine waters of the mangrove copses and river deltas, as well as in the rivers proper on the shores of the Indian Ocean from the Red sea to India, Malaya, the Philippines, Indonesia, and Northern Australia. The biggest archerfish reach 20-25 cm. The fry of these fish glow, but it is not real bio-luminescence, but a reflected green light, which, supposedly, helps these fishes, social as fry, to find each other.
The spearman is the swordfish. It was excellently described by Ernest Hemingway, who knew both the habits and the active, courageous attitude of the astonishing fish. It charges through the sea with the speed of a hurricane - 100-130 km/h. That is in the water, where the resistance is far greater than in the air. And how many birds can fly with such a speed?
Its' stylish 4-5-meter-long body (if the swordfish is really big) is pushed forwards by a half ton spring of muscle. The meter-long sword on the nose (the upper jaw is stretched forwards like a spear) cleaves the waves. This is both a hydrodynamic adaptation that lowers the frontal resistance of the water in the fish's way, and a dangerous weapon. Crashing into boats at a high speed the swordfish often pierced them. One of the boats was literally pierced through both sides! There's an excellent photograph - the witness of this incredible, supposedly, piercing power: the swordfish, stuck across the boat - the spear-like snout in one side, the tail's in the other. The anglers survived only because on sat on the prow, the second in the nose, and both fell into the sea from the blow.
The British museum keeps a piece of oaken board, covered in the front with copper, which was pierced clean through by a broken-off spear of the swordfish. The broken-off shards of the bone swords were found in the bottoms of the ships. Also in whales and sharks.
It is unknown, however, why the swordfish needs such pointless attacks? Are those accidental collisions, the result of unbridled fury, insanity for some reason...?
In any case, the composition of the head bones, especially at the base of the sword, is such in this fish, that the counterforce is experienced by it without any fatal after-effects in regards to itself. The empty spaces, filled with fat, the natural hydraulic amortisator, soften the counterblow.
These fish are not social, but around the swarms of mackerel or herring they gather in great numbers: each one came after its share of prey and keeps at a proper distance from the others. Like a hurricane they burst on the swarm, stun with the power of their strikes, slash and stab with their swords both squid and tuna, even the sharks (those that are not too big, of course).
The spawning of the swordfish is in the tropical waters of the oceans. To the south of the Sargasso Sea, for example, lies one of their biggest spawning grounds. Some breed in the Mediterranean Sea. Each female spawns many millions of eggs. The caviar floats in the water. The fry that hatch from them are unarmed with swords. But they grow up to 8 mm in length - and their noses stretch.
Meanwhile, the parents, after laying the eggs, scatter through the seas. Various sea fish goes to feed in the waters of the temperate latitudes, where's more food and the swordfishes follow them. Then they swim in our Black and Azov seas, sometimes into the Baltic. And in the north of the Atlantic ocean - to Iceland and Norway. Usually the swordfish hunt close to the surface, but they can submerge to the depths of 800 m.
The marlin, a close relative of the swordfish, is very similar to it: by the crazy attitude, by the magnificent jumps over the sea, and by the speed, which perhaps is even greater. In size some species of the marlin, perhaps, surpass the swordfish (length up to 5 m, weight 700, and perhaps even more, kg). Their upper jaws are also stretched, though far shorter than those of the swordfish are. This weapon is rather a rapier: round in the cross-section. The swordfish's is sharp at the both edges, flat as a sword.
Some species of marlins live in the open spaces of the tropical ocean zone. The sailfish and the spearfish - also belong to the Istiophorid family, just as the marlins are. And the swordfish are the only species of the Xiphiid family. Both of these families are joined into a special suborder of the Perciform order.
The sailfish have a very big (two-three times bigger than the actual body) and almost as long as the fish itself, dorsal fin. Moving quickly (up to 130 km/h!) its sail is folded as a fan into a special indentation on the back. At sharp turns, it seemingly grows from the back, working as a break and a stabilizer. The spearfish are similar to the sailfish, but their dorsal fins are much lower, and the tallest rays there are front ones, not the ones in the middle.
'On quiet days the sailfish may sometimes be observed at the very surface of the water, when they quietly drift with fully stretched and jutting through the water surface dorsal fins, possibly using wind power to move themselves. The biggest sailfish reach 3.3 m in length and weigh around 100 kg' (professor N.V. Parin).
In South America, in Guyana, Amazonia, the new arrival often hears such stories, for example:
'This happened on Rio Negro. (Or Rio San Francisco, Shingro, Aragua...) My father was yet a boy. They swam with grandfather to an island for the terrapins. And when the boat ran onto a sandbank - father fell into the water. (Possible versions: went to take a bath, to pull out a dead caiman, dropped by mother - it happens! In short, one way or another, he ended up in the river.)
Soon he safely got ashore. He walks and he senses - something's wrong... He hears: everything is loose and clanking within him. He looked at him... Great God! There was only the skeleton left...'
The understanding smiles of the interlocutors wordlessly explain the meaning of the joke, in which, as it often happens, there is a well-known portion of truth. Something similar does indeed happen in this country...
...The Native Americans of several local tribes, living at the edges of the swamps, where during the floods of the great rivers the entire neighborhood gets flooded, do not bury their deceased as usually, but first submerge them into the river water. After several hours they raise the bones from the water, and coloring them in traditional colors, they bury them when the floodwaters submerge, and green hills emerge in some places.
...This also happens: the wild peccary, fleeing from the jaguar, jumps into a river. It swims for several meters, and then the current bears its bloody body, and soon only the lifeless skeleton of a previously powerful beast dances the terrible dance of death in the water. Blunt-faced carnivorous fish, swimming in a large, dense pack, crowding each other, push and shove the skeleton, ripping away the remnants of meat from the body.
The piranha means 'slut' in Portuguese. Meanwhile, in zoology, it is the name of 12-16 species of fish of a specific family of the Characid fishes (order Cypriniformes). They are small fish: the biggest of them are 30-55 cm. But their bulldog jaws (the lower jaw protrudes forwards) - like the barbed maw of a trap! - are full of strong, deep-rooted and such sharp teeth, that a piranha can instantly bite in two a finger-thick stick. It will bite off a finger, too. The piranhas are a true nightmare. Wherever they are numerous, a rare person, even in the greatest heat, will risk going into water even to their knees. Never mind actual swimming, of course: they will quickly prepare him to the well-known anatomical 'specimen'.
The first conquistadors, who arrived with Orellian up the Amazon, already encountered the piranhas. Later on, few descriptions of these places and fewer films about the Amazon events do not talk about these fish. However, in our times, the doubts emerged: are really the piranhas so terrible? It was discovered that the natives are not so scared of them. They bathe and catch fish were the piranhas are plentiful. Wounds occur, but rarely. Few people are killed.
Only four are dangerous out of twelve or more species. The most terrible are the common, or the red-bellied, piranha - 'saikanga' in the native tongue - and black piranha, common in the watershed of the San Francisco River (one must added that it flows through the quite inhabited areas of Brazil). But even those do not always threaten people with an immediate and terrible death. The carnivorous attitude is usually demonstrated by the piranhas only when they are hungry or where the waste from slaughterhouses is dumped into the river. Up and away from such a place, though, they are no longer so dangerous. The stage of their aggressiveness depends from many, still unclear, reasons: how many of these fishes are in a certain areas (the 'group effect' with a critical number of approximately nine fish), of some, apparently, substances - the pheromones, excreted by the piranhas (if the water in the aquarium, for example, wasn't changed for a long time, the piranhas grow angry and attack each other).
In some rivers of Brazil the piranhas were tried to be killed off by various poisons. The effect for the objects of the destruction was insignificant, for the other inhabitants of water - quite noticeable. This should not be done, according to some specialists, because the role of these fishes, just as all other carnivores in nature, is sanitary and eliminating: they destroy most the sick, the weak, the degenerate animals, thus rejuvenating and perfecting the populations of their victims. In addition, these fishes are quite edible; they are often hunted, especially by the natives. The 'iron' jaws of the piranhas successfully replace scissors, and their teeth - knives, in the natives' households. The natives, armed with the blowpipes, according to Dr. Jacques Sheri, carry the teeth of the 'man-eating fishes' on their belts. Before firing the blowpipe, the poisoned dart is incised not far from the tip. The tip breaks-off in the wound and the poison acts quicker.
The relatives of the piranhas, which have settled across the ocean, in the rivers of Africa - the tigerfish - also occasionally attack swimming or bathing people. Their teeth are sharp as the stilettos. The goliath tiger fish is especially dangerous. It is thrice as big as the biggest piranha - up to 1.5 m - and weighs up to three stones! The tigerfish live and hunt in swarms, as the piranhas and the barracudas do.
'The barracuda too is quite safe for the underwater swimmers. If one discounts the long tales about the underwater world, I never read that a barracuda would attack a person. We often encountered barracudas in the Red sea, the Mediterranean sea, and in the tropical parts of the Atlantic, and none of them even showed an aggressive intent' (J-Y Cousteau, F. Dumas).
This statement of the famous experts of the 'silent world' sounds strange at the very least, few, apparently, would agree with it. (Including Hans Haas, a no less experienced diver than they are.) The reputation of the barracudas is very poor, the divers, especially the professionals, fear them in some places more than the sharks. Undoubtedly, the barracudas attack people. This is even done by the relatively small (1 m long) Mediterranean barracuda, which sometimes appears among us, in the Black sea. The bigger, two-three meters long barracudas attack without fear, as quick as lightning, and immediately depart after the first strike, do not repeat their attacks repeatedly, as the sharks do. But even from a single strike a big barracuda inflicts terrible wounds: the shock from the pain and the blood loss can lead to fatal results.
The barracudas resemble the pikes. They dwell near the coasts in the tropical and subtropical waters of all the oceans, in summer they visit the temperate waters too. The barracuda family (the Mugilid order) consists of 18 species. The smallest reach 30-50 cm. The biggest are up to 3 m and possibly more in length.
...Once, William Forster decided to take a walk in the town. He was a squatter, bred sheep, and lived on a farm in Queensland. Then he grew tired of it and he moved to Sidney. One day in 1869, Forster decided to look around the city.
He went to the museum. There he met Gerard Craft, the curator of the museum, and they talked. Forster asked among other things:
'Sir, why your museum has none of the big fish that live at our place in Burnette-River?'
'Big fish? What big fish?'
'The barramundi. We also call them the Burnette salmon. There are many such fish in Queens-land. They look like fat eels, five feet long. Their scales are thick and large. And can you imagine, only four fins. All are on their bellies.'
'You know, Forster, I've no idea of what fish you're talking about. It would be good for the museum to have a couple of such barramundi.'
Therefore, several weeks later the Sidney museum got a barrel delivered by the mail carrier, and in the barrel were the fish, strongly salted.
Craft literally froze when he saw them. Forster was correct: the fish were completely unbelievable, and they had only four fins. All on their belly. And all looked rather like flippers. And the tail was very peculiar: not forked, as in many fish, but wedge-shaped. The zoologists call tails of this type the diffecircular. This, perhaps, is the most ancient form of fish tails.
But the biggest surprise awaited Craft when he looked into the fish's mouth. He saw on the up-per and lower jaws plates made of teeth fused with each other (4 above, 2 below).
Paleontologists encountered such rasping teeth among the fossils for a long time, but none of the living fish had them. Professor Agassiz, a big expert on fossil fish called the owners of such strange teeth ceratodes, meaning 'horn tooth'. 400-200 MYA they inhabited the waters of our planet.
And now Craft held this ceratodus in his hands! He decided so, after closely examining the fish's teeth, and therefor without a doubt called the Burnette salmon the ceratodus. Later, paleontologists discovered not just teeth, but the skulls of the truly extinct ceratodes, and they proved to be not quite the same as that of the Burnette one. Therefore, the ichthyologists offered to add to its scientific name the specification 'neo' (i.e. 'new') or 'epi' (i.e. 'after'). However, more often, the barramundi is still called just the ceratodus or the horn-tooth without any specifications.
While studying the fish, Craft cut open one of them and found inside of it something even more astonishing... a lung! A real lung. The fish had gills, but also a lung. Hence, this fish breathed with both gills and lungs, making it a lungfish.
Before Forster decided to visit Sidney's museum, zoologists knew only two lungfish: the South American and the African lungfishes.
The South American and the African species have two lungs, and the Australian lungfish only one. The South American and the African species are closely related to each other. The ichthyologists united them into one order - the Lepidosireniformes. The fins on their bellies and chests are not 'flippers' as in case of the Australian lungfish, but dexterous, thin 'tendrils'. The Australian lungfish, as described by Craft, is a member of the second order, the Ceratodontiformes.
The Australian lungfish lives in slow-moving rivers, overgrown with water plants. They lie on the bottom, slowly crawl around, pushing against the bottom with their paired fins, slightly bending out the back in the manner of some caterpillars. They are not shy; the Australian lungfish can be caught by netting the lazy fish by hand. After every 30-50 minutes the Australian lungfish surfaces and putting its nostrils out of the water, (in the lungfish anatomy - the choanas), with a loud dense 'groan' it inhales the air. It is supposed that the Australian lungfish cannot manage without air breathing even in oxygen-rich water.
However, the Australian lungfish that lived for some time in the Berlin aquarium, according to the director and the staff, never surfaced to breathe air.
In the drought, when their native rivers dry out, the Australian lungfish do not burrow into silt. They crawl there, where moisture remains under the shade of shrubs, where's shadow and the sun is not so burning. They gather at the bottom of deep river pits and breathe, breathe... with their lungs. But they cannot last long like this. In big droughts the Australian lungfish die. And when the fate is kind, they live long - up to 60 years! And grow up to 2 m. Then they weigh-in at 50 kg.
'The Australian lungfish eat almost exclusively animals, primarily snails, but plants too, but they can adapt to eating only animals' (Hans Fry).
The Australian lungfish lay large eggs onto aquatic plants.
In 10-12 days the eggs hatch. The larvae lack external gills (the South American and African species have them). The eggs of the Australian lungfish are not sticky; therefore, birds do not carry them from one body of water to another, as they do with the eggs of many other fish: the Australian lungfish cannot use the 'air route'. Yet humans, worried about the fate of the rare fish, which survive only in the waters of the Burnette- and Mary-River, took and released them into some other Queensland waterways.
The African lungfish live in the overgrown, slow-moving, swampy rivers, but their most common and multiple settlements - in the lowlands that get flooded by rainwater for several months a year. When they dry out and the ground is covered by only few centimeters of water, the African lungfish dig burrows. The fish sucks silk - takes it into its mouth and spits out from the gills. Beneath the silt, it soon reaches the dense clay: the fish chews it; the bitten-off piece is ground and then exhaled with the water through the gills. The tiny pieces of soil float upwards in a murky cloud and then settle around the burrow. A ride forms around the entrance. When the burrows is finished, (with a 'bedroom' in the depths - a pear-like widening of the tunnel), the African lungfish will settle in it bending into two: with the end of the tail and the snout pointing upwards. It breathes, inhaling water and also soil that was extracted from the burrow and settled in a ridge around it: this forms a cork that plugs the entrance. The skin of such concealed African lungfish is plentifully slimy. They say that slime forms a cocoon around the fish - a very thin film: hundreds of an mm! Only where the mouth is located, the cocoon has a small hole for breathing.
"In this cocoon, as the experiments have established, African lungfish can live up to 4 years. During the hibernation the African lungfish shrinks in size and weight, at that the musculature of the fish is used up for energy needs' (Kurt Dekkert).
When the rains return, (after 6, or even 9 months), and the stone-hard silt gets moist and soft, the African lungfish emerges from the burrow.
At first it swims clumsily, its fins that got unused to moving gradually straighten and strengthen. These chest and belly fins, which resemble long whiskers or whips, the fish has the taste organs. By examining and sensing with them the murky waters, the dense underwater vegetation, the African lungfish learns without questions, what is edible and what is inedible. And reacts accordingly.
The spotted African lungfish in hibernation 'preserves' itself (in silt and the cocoon) only in the driest years. Usually in the Congo Rivers, where it lives, the swamps rarely dry-out completely; ground waters remain under the silt. In June - July, when the water level of rivers and swamps drops sharply, the male of this species digs a burrow on the bottom. Then it brings a female there in a manner still unknown to science. The female lays eggs and leaves, and the male guards the eggs and later the fry. The water leaves, the bottom, where the burrow was dug, can become revealed completely, but the spotted African lungfish and its offspring survive, (the male has the foresight to dig a mine from the nest chamber to the ground waters to provide water for the burrow). In the rainy season the new water frees the male and its' young from their underwater prison.
The other African lungfish (marbled, gilled African and West African) breed during the rainy season. About in a month after leaving the burrows.
The male digs a burrow in the shallows amongst the dense and tall vegetation: a horseshoe-shaped tunnel with the two entrances on the ends. In its' depths - a nesting chamber, with eggs: up to 5000 of them, usually from several females.
'Since the nests are made in the shallows, so to reach the deeper waters the African lungfish make peculiar 'paths', squishing and pushing aside the dense vegetation... Often these 'paths' go for several meters, and when the water level sharply drops... then the African lungfish have to reach water over dry land... The male cares about the nest and the young by itself. It... powerfully bites anyone who dares to approach it, does not back away from humans either, (the natives are afraid of its furious attacks). Even if it is chased out of the nest with a stick, then it fearlessly returns after several minutes' (V. M. Makushok).
The African lungfish can crawl on land as well as the river eels do. The marbled lungfish supposedly does it during the days when it is not weighted down by caring about the young. It leaves for the waters for the riverside silt and the nearby grasses apparently to feed on the small members of the wildlife of those lands. The experiments have shown: it gets only 2% of oxygen that is needed for breathing; the lungs give the other 98.
By sexual maturity the marbled African lungfish reaches 2 m, and the gilled - only 44 cm. The other species, the spotted and the West - about 100-130 cm.
The South American lungfish, their overseas cousin from the swamps of Paraguay and Brazil - up to 125 cm. But that is the limit even for the biggest South American lungfish. They all belong to a single species - Lepidosiren paradoxa, whose habits and lifestyle resembles the African ones. However, their behaviour is peaceful, in aquariums they easily coexist with other fish. The African lungfish chase and cripple each other and the other fish that put in with them.
When the swampy, overgrown lowlands where the South American lungfish lives, dry out in the drought, it too digs a burrow and waits for the rains in it.
'At that, it doesn't produce any slime... the fish builds an artful 'cork' from clay balls, which stick not quite fully to each other, so the air passes between them. As the ground dries out, the fish digs deeper, while making several more of such 'corks'' (Hans Fry).
It is pointless to look for them in the Southern Hemisphere. They are also absent in the African tropics (except for four species that live north of the Sahara desert). The same goes for India. It is hard to imagine these countries, rich with various beasts and birds, without such simple creatures, without newts, (we got them living in every pond!). However, beyond India's eastern border - southwards to Myanmar and Vietnam (but no further) - some tailed amphibians do live.
Only in South America, several species of lungless salamanders (tropical climbing salamanders) live south of the equator. Nowhere else in the world do the tailed amphibians cross this magical, for them, circle.
This order has eight families.
The Asiatic salamanders. These are primitive news. Around 30 species that dwell mostly in the montane areas of Eastern and Central Asia, only the habitat of the Siberian salamander reaches westwards to Europe - the Komi, the Gorkovskaya area.
The cryptobranchids. These are the biggest amphibians: the Japanese, the Chinese giant salamanders, and the North American hellbender.
The ambystomatidae. They are about 30 species of American salamanders (which live from Southeast Alaska to Mexico). They are usually neotenic (the neotenic larvae of the ambystomatidae salamanders are often called axolotls).
The 'true' salamanders and news. They are about 40 species in Europe, Asia, Northern Africa and North America.
The amphiumidae. They are three species (or three subspecies of a single species?) of strange amphibians, which resemble large (up to 1 m long) eels. The limbs are barely noticeable, each one has only three, or two, or even a single finger. (The number of fingers is the main way to distinguish be-tween the species.) They live in ponds, lakes, ditches, on the rice fields of southeast USA. They are active at night. From January to May they mate in the water: several females court a single male. The female incubates the eggs, curling around them, on land, in a wet pit. The amphiumidae have a world record, from a certain point of view: no other vertebrate has such giant blood cells - 75 microns. (In case of a human, they are ten times smaller.)
The proteidae. They are either two or 5-7 species, one of which, the European proteus or the olm, lives only in caves. The North American mudpuppies and waterdogs (1 or 4-6 species, according to var-ious taxonomists) dwell in fresh water bodies (not underground) of eastern USA and the adjoining areas of Canada. The common mudpuppy can reach 43 cm long. It hunts at night aquatic insects, worms, tadpoles and fishes. The females guard their eggs underwater.
The lungless salamanders. They are about 180 species that live mostly in North and Central America, two (cave-dwelling species) in Europe: in northwestern Central Alps of Italy and the adjoining areas of France, plus the island of Sardinia. Some species have crossed the equator (the only ones amongst the tailed amphibians) and settled in South America (up to the Amazon).
The sirenidae. They are the three species of freshwater southeast USA. They are quite large reptiles (the greater siren can be up to 1 m in length). They are eel-like but with bunches of external gills to the side of the head and a pair of tiny front legs (there are no hind legs). Some taxonomists believe that this family deserves to be made into an independent order of their own.
THE GIANT SALAMANDER AND THE AXOLOTL 'THAT PLAYS IN THE WATER'
Compared to any newt, any frog, a giant salamander is a giant. 1-1.5 m - an excellent size for any amphibian. Moreover, the weight is impressive too - 8-10 kg.
Millions of years ago, such salamanders were plentiful in North America, Europe and Asia. Now, there are only three species: the Japanese giant salamander (the biggest amphibian in the world!), its' Chinese relative (a species or a subspecies?) and the North American hellbender. In all cases, their appearance is significantly infernal: the body is flattened, loose skin forms folds on the sides, the flat 'catfish-like' head are warts and near-sighted eyes, apparently so imperfect, that they distinguish only light from darkness.
A giant salamander, from birth to death, lives in free-flowing streams and rivers that do not freeze in winter. During the day, it aimlessly sleeps under ravines, under rocks, in underwater burrows. At night, it crawls on the river bottom, hunting frogs, crayfish, fish, worms and insects. At the end of the summer, the females find males in their inhabited burrows and lay their eggs there. The males, ceremonilessly having kicked them out, (sometimes the females devour their own eggs!), keep watch over the eggs, ventilating the space, sending fresh water with tail sweeps. In two months, the parental care is over: the larvae hatch.
The meat of these salamanders is tasty, they are being hunted. Few of them are left, especially in Japan. Probably in China too.
'The fairly small family of ambystomas includes 28 species... The overwhelming majority is located in the ambystoma genus, (21 species), widely distributed and well known due to the neotenic larvae, which are locally called 'axolotl' ('player in the water') (Professor A.G. Bannikov).
In nature, the axolotl lives only in the Sochimilko Lake... The name belongs to the Aztecs, when translated it means 'water monster' (Gunther Freytag).
So, the ambystomas. Their homeland is America. They resemble European salamanders, but their eyes are smaller and their life is even more reclusive (in various places underground). This is why the Americans call the ambystomas the mole salamanders. In spring (montane species - in summer), the ambystomas move to ponds and streams and reproduce there. The larvae become adult salamanders in twelve or eighteen months, and some never transform at all! Such, for example, is the now well-known axolotl, a frequent visitor of scientific labs, zoo stores and nature corners in schools. Its' neoteny is inherited. It is passed from generation to generation, even to the hybrids of the axolotl with, say, the tiger salamander. It is an eternal larva (like a caterpillar, which, having not become a butterfly suddenly started to reproduce!). However, you can make it 'grow up', subscribing it several shots of thyreodine or feeding it a thyroid gland. It is these hormones that control the amphibian metamorphosis. In the case of the axolotl, this gland is underdeveloped. After the endocrine 'therapy', the axolotls transformed into Mexican ambystomas, very similar to the tiger salamanders.
The global expansion of the axolotls in the laboratories of the world started small: the natural habitat is miserably puny. The mountain lake Sochimilko is 35 square km. It is approximately twenty miles south-east from Mexico. Actually, it is not even a lake - more of a tangle of channels, ponds and streams that form a single water system. The biggest streams are no more than 20 m wide, and most are so small, that the flat Native American canoes can barely swim through them.
There the axolotls are caught and sold on markets in the nearest villages and in Mexico.
FIRE-BELLIED TOADS, MIDWIFE TOADS AND SPADEFOOT TOADS
A fire-bellied toad resembles an ordinary small toad, grey or black on top, orange on the bottom with black spots. Its' monotonous call has provoked a reaction among the people: 'Listen to the newts hoot!'
Newts are soundless from birth... Why the names were switched is unknown.
The piping, monotonously delicate voices of the fire-bellied toads produce an atmosphere of sadness. A male fire-bellied toad will lie, stretched out, on the surface of a pond. It emits its inviting cry while vibrating its body. A circle will ripple outwards through the surface of the water. The male will jerk forwards - emit its cry once more and the water will ripple. If you get up to look at it from a better angle, the fire-bellied toad will immediately dive. However, from the bottom, its' almost relentless cry will sound, just quieter.
During warm weather, male fire-bellied toads cry 18-20 times a minute. When a second male will join the first, the first male, falling silent for a moment, will try to echo the second male in harmony, but not in union, and then they 'sing' with intervals, as if there was only one male around. However, if the leading voice will not find the needed tone (it will sing too slowly or too fast), a cacophony will result. Thus, often, an experienced naturalist will break up the harmony of the fire-bellied toads' song, trying to imitate them: they accept him, but the person, not always sufficiently musically gifted, will mess up the centuries-old synchronization of those small-sized choruses.
The eggs are attached at night to plants and other objects found underwater. Approximately, in a week, the tadpoles will hatch. In three months, if the weather is warm enough - even earlier they transform into froglets (in July - August). Then the autumn gets replaced by winter and the fire-bellied toads move into the burrows of mice, voles, into lose shoreline soil, sometimes they winter underwater.
The skin of the fire-bellied toads is poisonous. Not as much as, say, of the poison-arrows frogs, but much more so than in case of most other temperate toads. The fire-bellied toad warns about its' inedibility thus: it turns its black-and-red belly up! When it is frightened, it gets covered with a poisonous foam-like slime. Take care of the eyes, so that the fire-bellied toad's slime will not get into them. Even if you just drop low above the 'foaming' amphibian, the eyes might tear-up and itch.
Only the fire-bellied toads represent the alytid family in the former USSR. However, in Western Europe, there are midwife toads as well. You will not be wrong if you decide that the strange name 'midwife' is directly related to the midwife in question. Scientists have decided upon this more than 200 years ago. However, this is not easy to see. The midwife toad almost does not appear aboveground during the day. Only during nights. Therefore, for many, including rural inhabitants, it is a 'persona incognita', i.e. an unknown creature.
In March - April, as soon as the sun will melt the snow, the midwife toads awake, after spending the winter in burrows, caves and basements. Then, especially in the favored sandy hills and foot-hills, during warm evenings, from sunset and until darkness, the melodical voices of their males will sound. The females cry too, but more quietly and rarely. The mating meetings usually take place 50-100 m away from the nearest body of water.
The eggs are 'packaged' into long slimy cords (up to a meter and longer). The male immediately wraps them onto...its thighs! It grabs a cord with two middle fingers of the left hind leg and wraps a noose onto its right thigh. Then, with its right foot, onto its left thigh. In 10-20 minutes the job is over. The male pushes the heavy load on its back and goes where it is more dump and more out of the way (or cries once more, summoning another girlfriend, to load its eggs on top of the first batch). The male midwife toads hides under roots, in burrows, and does not leave the eggs at night. After 18 (if the weather is warm) or after 30-50 days (if the weather is cold), from the eggs, guarded by the male, the tadpoles should hatch. In addition, the male begins to journey to water. (If you catch and try to take the eggs away, it will piteously cry, try to clumsily fight you off. It will not give the eggs up without a struggle!)
Usually sitting in the shallows thusly, so that only the butt is wet, the male midwife toad, loaded with eggs, patients waits when its offspring, twitching their tails, break through the eggs and swim away. Their nanny, ripping on the algae the remnants of the eggs, will climb to the shore, where it leads a life that is just as private as that of its relative (albeit from another family) - the spadefoot toad.
The latter lives almost everywhere - in the Russian valleys, mixed and broadleaf forests, steppes: from the western border almost to the Irtysh river. In addition, how many people know of this amphibian? It is very reclusive. During the day, you can only accidentally discover it while doing earthworks - in ravines of sandy or clay soil. Alternatively, during the spring - in the water: here the spadefoot toads lay eggs. Without emerging or sitting on hillocks they bubble from some-where in the depths... In addition, later, possibly, the local people there will meet very large tad-poles: 7-10 or even 17.5 cm long.
The spadefoot toads are yellow-brown or grey amphibians (6-8 cm long), with a back with dark spots, smooth and not bumpy as it is in the common toads. Now look at its eyes - if the pupil is vertical, then this is a spadefoot toad for sure. Only in the Caucasus, one can meet two tailless amphibians with a vertical pupil - the Syrian spadefoot toad and the Caucasian parsley frog. (The fire-bellied toads have a more-or-less triangular pupil.)
One can also smell their ambiguous catch: often the spadefoot toad reeks off... Of course, of garlic! If this is not enough - take a look at the hind legs: from the inner side there should be a large, with a sharp edge made of hardened skin, bump. This is a shovel for digging, to be able to dig quickly enough (in 2-3 minutes) into soft soil, beneath which the spadefoot toad spends the sunny hours of a day, giving up the surface of the land and of the water for the other tailless amphibians.
Borneo, Sumatra, Philippines... Forests, shrubs, tall grasses at the water edge... Here lives the famous leopard flying frog. It is also called the Borneose. It looks thusly: green, with sides and stomach in dark spot, (a leopard pattern). The edges of the hind legs and the fingers on the forelegs are orange.
In addition, between the fingers of all legs, are wide webs. The frog unfurls them - and a parachute is made! The frog jumps from a tree - the parachute halts the fall and prolongs the flight! The greater is the height that the amphibious pilot started from, the further it glides. If you measure on the ground the distance from the tree on which the jump started, then it will be approximately equal to the three fifths of the height from which the frog started.
Many leopard parachutists gather at night on trees that grow at the water edge. Males play on 'drums': their cries resemble the sounds of a balloon, drummed by a finger. The females have more important things to worry about. Selecting the lower, overhanging the water, branches, roots, rocks, they make nests on them: foamy at first, and then they get covered with a hardened brown crust. They are made from some froggy liquid that the female frog intently whips with hind legs, just as a housewife whips cream. The foamy hat is located on a leaf or in a 'bundle' - between two or three leaves. The frog hides the eggs in this foam. On top, the foamy cradle soon forms a crust, and inside it remains moist for a long while. The tadpoles will hatch from the eggs and break through the walls of their house, (or rainstorms will wash it down from leaves). They will fall below, into water, where they will live until they become froglets.
The flying frogs are from the Rhacophoridae family: all of them, (it consists of 400 species!) have small bulges, spheres, on their fingertips. When a flying frog puts its legs onto a leaf or onto the bark, the spheres flatten into disks, forming suckers. The suckers keep the frog's legs even on the smooth and sheer surface of leaves and tree trunks, where the Rhacophoridae frogs live. Africa, Madagascar, South-East Asia, (up to Japan in the north) - in this wide space, inhabited by the Rhacophoridae frogs, the flying frogs live only in Asia. The Borneo species was already talked about. Java and Sumatra have the Javanese flying frog, (emerald-green, yellowbellied, the youngsters have blue spots on their webbing!), and one more, with black legs, in the jungles of Borneo, Sumatra, Malaya and Laos. This one, probably is the best glider of all. Having jumped from the top of a five-meter tree it will fly away from it a seven-meter distance!
Certain South American tree frogs can also fly some.
Foam nests are most typical among the Rhacophoridae frogs. Sometimes the males help with the foam too. Some sit at the nests for a week and more, protecting them.
The African grey foam-nest frog works in pairs. Then the female, putting into the foam pile, (the size of a bean), 150 white eggs, sits onto it and firmly hugs it with all four limbs. The time passes; the mother frog sits on eggs and does not leave. Everything around it dries-out from the heat... But then the frog seems to regain its' senses, it twitches its' legs and starts to move. It crawls down the branches - to the water beneath the nest. It dived into a pond, lay a bit, absorbing moisture through its' skin. In addition, it climbs upwards once more. It moistens, (by spraying from its' cloaca) the 'bean' with eggs, and shades it from the sun. If the mother dies, or the strong heat will fully dry out all of the bodies of water in its' immediate surroundings, there will be nothing to water the 'bean', then it becomes as tough as carpentry glue, and the tadpoles cannot escape it...
The foam-nest frogs are also from the Rhacophoridae group - they are the so-called grasping frogs. That is, they do not grasp their prey or anything else, but tree branches. Two internal fingers, moving sideways, oppose, as the biologists say, the other fingers, just as thumbs do on our hands. Branches thus are grasped firmly and the frog climbs them as a primate does. Many Rhacophoridae frogs have tadpoles, (and the tadpoles have their metamorphosis in water, where they fall from their nests). However, in some species the eggs hatch directly into froglets.
The Rhacophoridae make nests for their eggs in bent leaves and hang the eggs on leaves and stems that are located above water, and bury them not far from water into the soil or into fallen leaves. In addition, the Sri Lankan Rhacophorus frog carries its eggs on its' own body, pressed into a tight disk on the frog's stomach! In short, the wide family of the Rhacophoridae frogs take care of their young in very different ways. The same goes for the ecological habits of these frogs. Many live high in the leaves. To see and catch them is hard work for biologists. Others jump and climb among shrubs and grasses, and some live in dry savannas, and hide, as spadefoot toads do, from the heat underground. These earth-digging relatives of the 'pilots' have atrophied webs ad sticky suckers. However, the Japanese singing frog kept them. It lives in rapid mountain streams: a firm adherence to sticky stones is most necessary here. The cries of the singing frogs are pleasant, just as the bird calls are.
'In Japan, these singers are sold in the markets, and the best of them are expensive'. (M.N. Denisov).
Their mismatched choruses are a necessary accompaniment to all of the sounds that feel the summer nights, of course, in sufficiently damp places. 'Worr... worr... worr... kruu!' - methodically, loudly, huskily. Suddenly, a sharp - 'kre-kre-kre... nek-nek-nek' - a croaking solo of one or another male, bursts out like a loud crescendo from the monotonously sounding cry. These are green marsh frogs.
In small, usually stagnant bodies of water, in ponds, forest pits, in simple puddles and ditches live smaller, but also green frogs - the pool frogs. They are brighter, more emerald, and their cries are not as loud and rough: 'Koax, koax, koax...'
Suddenly, a loud, vibrating cry: 'Rekkekkekke!', and once more: 'Koax... koax... koax...' They inflate sound-amplifying, white or yellowish resonators - spheres in the corners of their mouths.
The marsh frogs have grey, or even black, resonators. When the resonators are not inflated, they can be seen from below and behind the corners of the mouths, looking as thin, long, dark spots. The marsh frog is bleaker in color than the pool frog is; it is often olive in color, sometimes even brown, with black and dark green spots and a bright stripe running through the middle of the back. It is the biggest Russian frog - from nose to the end of the tail it is 9-15 cm, and sometimes even 17. In addition, the most carnivorous: the marsh frog attacks even vertebrates! Not big ones, of course. Fish fry, tadpoles, adult tree frogs and moor frogs, even young grass snakes, shrews, young voles and small birds! However, such cases are rare.
The male pool frogs are smaller than the females are (the average lengths is 7.5 cm in males, 9 - in the females). The marsh frogs' females are not much larger than the males are. The pool frogs, as it was said already, are usually elegantly emerald, like the vibrant pool plants are. However, there are also yellowish-, or grey-green, and very rarely - bronze-brown, even bluish in color. Their Latin name 'esculenta' in translation means 'edible': the people, which eat frogs, prefer the pool frogs to the others. Their meat is indeed very tender, like a young chicken's. However, according to the experts, the ordinary, common frogs that we meet in field and forest are even tastier!
They are brown, in various shades. Below, on the bottom - a marbled mottled design, with the basic color being dirty white (for the males) or brownish-yellow, reddish-brown (for the females). A monotonously light belly (without any spots) is very rare.
If a frog with such belly is caught, then it is usually the moor frog. It is also brown in color; in size, it is smaller than the common frog is. It is usually found in copses, meadows, swamps, steppes and scrub-land, in gardens too, as is the common frog, actually.
Both frogs also in the boreal forests beyond the Arctic circle, but the common frog in places goes further north that the moor frog does, for example on the Kola Peninsula, (the moor frog isn't found there), and throughout the entire Scandinavia, up to the North Cape. However, the moor frogs are prevalent in the steppes. They more easily endure the heat and the dryness.
The common frog is the most northern of all the frogs, and, probably, the quietest one. Its' quiet purring croaking can be heard, (often from beneath the water), in spring, when the common frogs breed. There is still ice in places on lakes and pools, but they have already woken up from hibernation be-neath the waters and are busy laying eggs. (The moor frogs usually winter on land. Some western scientists believe that the sexually immature common and pool frogs, as well as possibly some others, also winter on land.)
In Kiev's suburbs the first frogs appear at the end of February, (if the spring is early), in Moscow's - in March-April, and in northern France - in January. They will lay in the water their viscous knots of eggs and will soon leave to travel on land (the green-skinned frogs, the marsh and the pool frog, live all summer long in water and near it).
In April - in the beginning of May the moor frogs are plentiful - they lounge in crowds in the shallows of sylvan swamps, in forest clearings and lowlands, flooded with spring waters. The males of the species at that time are celestial blue in color! The beautiful sky shade of the frogs' skin is produced by lymph, which fills the skin. Have you seen blue frogs in spring?
Day and night, the supposedly quite voices of the moor frogs can be heard from afar, filling the Russian forests. They endlessly cry 'Ko-ko-ko'. You listen and you think: 'When will they take a rest, quiet down at least for some time?..' You move further away - it is as if gamebirds were crying on their lek.
The family of true frogs has more than 400 species. Among them the prominent ones are:
In size and weights - the bullfrog (southeast USA) and the goliath frog from Western Africa (Cameroon, Angola). The first species is already sizeable (20 cm), but the second... The second is the biggest among all the frogs and toads - 33 cm. Moreover, one of them, caught in Angola, was 40 cm long, 24 wide. It weighted 5 kg. The eyes were only slightly smaller than a human's, and the thighs were as thick as a human's wrist!
In unusual hirsuteness! In Western Africa (from Guinea to Cameroon) the males of some frogs... grow hair when the mating season comes. Quite long ones, in fact - one to one and a half cm. It is truly a beard! However, not where we are used to seeing it, but on thighs and sides. Why does a frog need 'hair'?
Most likely: the 'hairs' are extra organs to breathe through skin. They are not real hairs, of course, but thin, hair-like, outgrowths of skin, densely penetrated with blood vessels. However, how are they useful to a frog that lives and breeds in oxygen-rich, freely flowing water? In bodies of water so freely flowing, that only eggs glued to rocks, are not taken downstream. The tadpoles, hatched from these eggs, are excellent swimmers, but without powerful sucker-mouths, they too would not last among the rocks. Therefore, says the famous specialist of amphibians, the Swiss scientist Hans Hoiser, until their true designation in life won't be proven, these 'hairs' should be treated as decorations.
In exceptional toxicity! These are the poison dart frogs. They are smallish, but brightly and powerfully colored frogs of Central and South America. Their skin secretions are so toxic, that the birds and monkeys, struck with poisoned darts, immediately fall out of trees, paralyzed.
The arming of the darts begins with when the poison dart frogs are caught, the Native Americans first warm them up: hold them above a fire stuck on a stick. The poison drips from the skin of the wretched animals into the vessel held below. It is a neurotoxin. It is dangerous for people too.
For the scientists, who study animal behavior, the poison dart frogs are some of the most interesting members of the amphibians. All inhabited territory is firmly divided into individual zones. 'A border pillar' and the main HQ is usually some object that dominates the neighborhood. A big stone or a rotting trunk of a cast-down tree. Usually it is guarded by the female. The male takes care of the young.