Report about a sea turtle. Sea turtle. Reproduction of sea turtles

A turtle is an animal of the chordate type, class Reptiles, order Tortoise (Testudines). These animals have existed on planet Earth for more than 220 million years.

The tortoise got its Latin name from the word “testa”, meaning “brick”, “tile” or “clay vessel”. The Russian analogue came from the Proto-Slavic word čerpaxa, which in turn came from the modified Old Slavic word “čerpъ”, “shard”.

Turtle - description, characteristics and photographs

turtle shell

A characteristic feature of turtles is the presence of a shell, which is designed to protect the animal from natural enemies. turtle shell consists of a dorsal (carapace) and abdominal (plastron) part. The strength of this protective cover is such that it can easily withstand a load exceeding the weight of the turtle by 200 times. The carapace consists of two parts: internal armor made of bone plates, and external armor made of horny scutes. In some species of turtles, the bony plates are covered with thick skin. The plastron was formed due to the fused and ossified sternum, clavicles and abdominal ribs.

Depending on the species, the size and weight of the turtle vary significantly.

Among these animals there are giants weighing more than 900 kg with a carapace size of 2.5 meters or more, but there are small turtles whose body weight does not exceed 125 grams and whose shell length is only 9.7-10 cm.

Head and eyes of a turtle

Turtle head It has a streamlined shape and medium size, which allows you to quickly hide it inside a safe shelter. However, there are species with large heads that fit poorly or not at all into the shell. In some representatives of the genus, the tip of the muzzle looks like a kind of “proboscis” ending in nostrils.

Due to the peculiarities of the way of life on land, the turtle's eyes look at the ground. In aquatic representatives of the order they are located closer to the top of the head and directed forward and upward.

The neck of most turtles is short, however, in some species it can be comparable to the length of the carapace.

Does a turtle have teeth? How many teeth does a turtle have?

To bite and grind food, turtles use a hard and powerful beak, the surface of which is covered with rough bulges that replace teeth. Depending on the type of food, they can be razor-sharp (in predators) or with jagged edges (in herbivores). The ancient turtles that lived 200 million years ago, unlike modern individuals, had real teeth. The tongue of turtles is short and serves only for swallowing, and not for capturing food, so it does not stick out.

Limbs and tail of turtles

A turtle has a total of 4 legs. The structure and functions of the limbs depend on the animal’s lifestyle. Species that live on land have flattened forelimbs adapted for digging and powerful hind legs. Freshwater turtles are characterized by the presence of leathery membranes between the toes on all four paws that facilitate swimming. In sea turtles, during the process of evolution, the limbs have been transformed into a kind of flippers, and the size of the front ones is much larger than the back ones.

Almost all turtles have a tail, which, like the head, is hidden inside the shell. In some species it ends in a nail-shaped or pointed spine.

Turtles have well-developed color vision, which helps them find food, and excellent hearing, which allows them to hear enemies at a considerable distance.

Turtles molt, like many reptiles. In land species, molting affects the skin in small amounts; in aquatic turtles, molting occurs unnoticed.

During molting, transparent shields peel off from the shell, and the skin from the paws and neck comes off in rags.

Lifespan of a turtle natural conditions can reach 180-250 years. When winter cold or summer drought sets in, turtles go into hibernation, the duration of which can exceed six months.

Due to the weakly expressed sexual characteristics of turtles, it is very difficult to determine which of the animals is a “boy” and which is a “girl”. However, if you approach the issue carefully, having studied some of the external and behavioral characteristics of these exotic and interesting reptiles, then finding out their gender will not seem such a difficult matter.

• Carapace

In the female it usually has a more elongated, elongated shape compared to the male.

• Plastron (lower part of the shell)

Turn the turtle over and look at it carefully - the shell on the side of the abdomen closer to the anus in female turtles is flat, in males it is slightly concave (by the way, this nuance facilitates the mating process).

• Tail

Male turtles have a tail that is slightly longer, wider and thicker at the base, most often curved down. The tail of the “young ladies” is short and straight.

• Anal opening (cloaca)

In females it is located somewhat closer to the tip of the tail, shaped like an asterisk or a circle compressed on the sides. In male turtles, the anus has a narrow oblong or slit shape.

• Claws

In almost all species, except the leopard tortoise, the claws of males on the forelimbs are longer than those of females.

• Notch at the tail

Males have a V-shaped notch in the back of their shell, which is necessary for turtles to mate.

• Behavior

Male turtles are most often more active, and during the mating season they are distinguished by their aggressiveness towards their rival and towards the “lady of the heart”, they chase her, trying to bite her, and nod their heads funny. At this time, the female can calmly watch the “courtship”, hiding her head in her shell.

• Some species of turtles have specific differences between females and males, such as color, size or head shape.

Types of turtles - photos and descriptions

The tortoise order consists of two suborders, divided by the way the animal retracts its head into its shell:

• Hidden-necked turtles, folding their necks in the shape of the Latin letter “S”;
• Side-necked turtles, hiding their head towards one of their front legs.

According to the habitat of turtles, there is the following classification:

• Sea turtles (live in seas and oceans)
• Terrestrial turtles (live on land or in fresh water)
  • Land turtles
  • Freshwater turtles

In total, there are more than 328 species of turtles, forming 14 families.

Types of land turtles

• Galapagos tortoise (elephant) (Chelonoidis elephantopus)

The length of the shell of these turtles can reach 1.9 meters, and the weight of the turtle can exceed 400 kg. The size of the animal and the shape of its shell depend on the climate. In arid areas, the carapace is saddle-shaped, and the limbs of the reptile are long and thin. The weight of large males rarely exceeds 50 kg. In a humid climate, the shape of the dorsal shell becomes dome-shaped, and the size of the animal increases significantly. The elephant tortoise lives in the Galapagos Islands.

• Egyptian tortoise (Testudo kleinmanni)

a small representative of land turtles. The size of the carapace of males barely reaches 10 cm, females are slightly larger. The color of the shell of this type of turtle is brown-yellow with a small border along the edges of the horny scutes. The Egyptian tortoise lives in northern Africa and the Middle East.

• Central Asian tortoise (Testudo (Agrionemys) horsfieldii)

a small reptile with a shell size of up to 20 cm. The carapace has a rounded shape and is colored yellowish-brown with darker spots of uncertain shape. These turtles have 4 toes on their forelimbs. The most popular type of turtle for home keeping, lives about 40-50 years. Lives in Kyrgyzstan, Uzbekistan, Tajikistan, Afghanistan, Lebanon, Syria, northeastern Iran, northwestern Pakistan and India.

• Leopard tortoise (panther tortoise) (Geochelone pardalis)

The carapace length of this turtle exceeds 0.7 m, and the weight can reach 50 kg. The shell of this type of turtle is high and dome-shaped. Its color has sandy-yellow tones, on which in young individuals a spotted pattern of black or dark brown is clearly visible, disappearing as they grow older. This species of turtle lives in African countries.

• Cape speckled tortoise ( Homopus Signatus)

the world's smallest turtle. The length of its carapace does not exceed 10 cm, and its weight reaches 95-165 grams. Lives in South Africa and southern Namibia.

Types of freshwater turtles

• Painted turtle (decorated turtle) (Chrysemys picta)

A rather small species of turtles with individual sizes ranging from 10 to 25 cm. The upper part of the oval dorsal shell has a smooth surface, and its color can be either olive green or black. The skin has the same color, but with different stripes of red or yellow tone. They have leathery membranes between their toes. Lives in Canada and the USA.

• European marsh turtle (Emys orbicularis)

The size of individuals can reach up to 35 cm and weight 1.5 kg. The smooth, oval carapace is movably connected to the plastron and has a slightly convex shape. Representatives of this species have a very long tail (up to 20 cm). The color of the upper shell is brown or olive. The skin color is dark with yellow spots. The turtle lives in European countries, the Caucasus, and Asian countries.

• Red-eared turtle (yellow-bellied turtle) (Trachemys scripta)

The shell of these turtles can be up to 30 cm long. Its coloring is bright green in young individuals, over time it turns into yellow-brown or olive. Next to the eyes on the head there are two spots of yellow, orange or red. This feature gave the species its name. lives in the USA, Canada, northwestern South America (northern Venezuela and Colombia).

• Snapping turtle (biting) (Chelydra serpentina)

A characteristic feature of a turtle is a cross-shaped plastron and a long tail, which is covered with scales with small spines, as well as the skin of the head and neck. The shell dimensions of these turtles can reach 35 cm, and the weight of an adult animal can be 30 kg. The snapping turtle waits out unfavorable conditions in hibernation. This turtle lives in the USA and southeastern Canada.

Types of sea turtles

• Hawksbill turtle (true carriage) (Eretmochelys imbricata)

The carapace of these turtles is heart-shaped and up to 0.9 m in size. The upper layer of the shell is painted in brown tones with a pattern of multi-colored spots. In young individuals, the horny plates overlap each other like tiles, but as it grows, the overlap disappears. The front flippers of the animal are equipped with two claws. The hawksbill lives both in the latitudes of the northern hemisphere and in southern countries.

• Leatherback turtle (Dermochelys coriacea)

this is the largest turtle in the world. The span of its front flipper-like limbs reaches 2.5 meters, the mass of reptiles is more than 900 kg, and the dimensions of the shell exceed 2.6 m. The surface of the upper shell is covered not with keratinized plates, but with dense skin, for which the species received its name. The turtle lives in tropical areas of the Atlantic, Pacific and Indian oceans.

• Green turtle (soup turtle) (Chelonia mydas)

The weight of the turtle ranges from 70 to 450 kg, and the size of the shell is from 80 to 150 cm. The color of the skin and carapace can be either olive with a green tint or dark brown with various spots and stripes of white or yellow. The turtle's shell is short and oval in shape, and its surface is covered with large horny scutes. Due to the large size of their heads, these reptiles do not hide their heads inside. The green turtle lives in tropical and subtropical waters of the Atlantic and Pacific oceans.

Even a person completely far from biology recognizes this amazing animal at first sight. Sea turtles have long been considered a symbol of benevolence and wisdom. But in order to keep such an animal at home, avoiding the occurrence of various problems, the owner needs to know in what conditions turtles live and how they feed in their natural environment.

Features of sea turtles

These animals have practically lost contact with land, spending all their time in the water and only coming to land to lay eggs. Turtles look very helpless and clumsy on the shore, but in the water they are very agile and can even develop quite high speeds.

Representatives of these animals are united by very developed front paws in the form of flippers and a massive head located on a short neck. The streamlined, heart-shaped shell has a bony base and is covered with many horny scutes. A peculiarity of sea turtles is that neither the head nor the limbs are able to retract under the shell.

Even the smallest representatives of these animals have a mass of up to 50 kg and a shell length of 50-70 cm. There are also real giant sea turtles. These include the green turtle, whose shell reaches up to 120 cm in length and sometimes weighs more than 300 kg.

Reproduction and lifespan

Sea turtles reach sexual maturity at 25 years of age. Having spent their entire lives away from the coast before this period, at the time of nesting they rush to land, namely to the place where they themselves were born. Mating takes place near the shore, after which sea turtles prepare a nest in the sand, into which they lay up to 200 eggs. After that, they go to sea, not interested in what will happen to the clutch in the future.

After 2 months, baby turtles are born. Their sex depends largely on temperature environment- at low temperatures, males are born, and at high temperatures, females are born. Small turtles are hunted by all and sundry, so very few individuals survive to adulthood. As a rule, out of 100 cubs born, only one survives. These animals are known for their longevity. Their lifespan can reach 80 years.

Sea turtles: species

Recently, it has become a fashionable trend to keep exotic animals in the house. Most often you can find a turtle in home terrariums. But in order to provide it with optimal conditions, it is necessary to determine its type. The lack of basic knowledge of the biology of these animals and especially what sea turtles eat often leads to their death. There are several types of these reptiles.

Hawksbill turtles are widespread in the tropical zone. Their brown shell consists of plates overlapping each other and has 3 longitudinal ridges. There are barely noticeable yellow spots on both the shell and the head. This turtle is a predator and feeds mainly on small and large animals. The speed it develops in water allows it to hunt fish, and its sharp and strong jaws help it bite through mollusk shells. The length of the shell can reach 85 cm. Hawksbill sea turtles are quite unpretentious, so they are quite suitable for home keeping.

The loggerhead is larger in size; its shell can be up to one meter long and consists of five pairs of brown-red horny scutes. The main part of the diet consists of shellfish, fish, crabs and algae. The large size of this turtle does not allow it to be kept at home.

The olive turtle (Ridley) does not exceed 80 cm in length. The grayish-colored shell has several costal scutes. The turtle feeds on algae, crabs and shellfish, sometimes hunting small fish.

Green sea turtle

This is another species that deserves special attention, because it is considered the largest among all others. Some turtles can weigh up to 400 kg. The horny scutes of its shell are tightly fastened together, and do not overlap one another, as in other representatives of these reptiles. The size usually does not exceed 70 cm, the average weight is about 200 kg, but sometimes very large individuals are found, up to 150 cm in size and weighing 350-400 kg. These are real giants among all representatives of turtles. Therefore, they are very rare in home terrariums; usually these are only young turtles, the size of which is no more than 10 cm.

The color of the shell depends on the turtle’s habitat and can be black, brown or dark green. Each flipper-like limb has a large, sharp claw. The green turtle feeds mainly on vegetation, occasionally on fish and seafood.

Red-eared sea turtle

This is the most common inhabitant of home terrariums. Red-eared sea turtles have medium-sized shells (up to 30 cm) and are distinguished by wavy white-green stripes located on the neck, head and limbs. They got their name thanks to the bright red spots located near the eyes. In young turtles, the shell is green in color, and with age it becomes brown or olive in color. In water, these reptiles are unusually mobile and can compete in speed with fish. They are no less agile on land, which makes it easy to hide from enemies.

The absence of teeth does not prevent the turtle from biting its offender. She does this due to her very strong jaw muscles, inflicting serious wounds when she needs to protect her life.

At home, these sea turtles can scratch the skin quite severely with their strong claws located on the hind limbs. This often happens if you take them out of the water carelessly. This must be done very carefully, without squeezing the shell and keeping the turtle away from exposed skin.

Despite the fact that these animals prefer the water element, when kept at home they also need land space. Small special islands can be purchased at a pet store. The volume of a terrarium for an adult turtle should be at least 100 liters. Water for the terrarium must be settled, and it must be changed at least once a month. Installing an incandescent lamp directly above an island of land, where a turtle can always crawl out to warm itself, will help create an optimal temperature of 25-30 ⁰C. Such conditions are as close as possible to the natural ones to which turtles are accustomed in the wild.

What to feed a sea turtle

In order for a turtle to live a long and fulfilling life in the house, it is very important to properly prepare its diet. To do this, you need to know what sea turtles eat. The menu must include meat products ( veal heart, minced meat, liver, poultry), as well as bloodworms, worms, small frogs, tadpoles, etc. In addition, it is necessary to give marine varieties of fish, seafood, snails, plant foods such as dandelion greens, beets, carrots, vegetables and fruits. Fish should be fed only boiled, carefully freed from bones. The meat is cut into thin strips.

In the wild, red-eared sea turtles usually grab food in the water and crawl ashore to eat it. It’s a good idea to accustom your pet to this ritual, then the water will not be polluted by food getting into it. You can place the turtle in a special basin for eating, which will help keep the aquarium clean. It is recommended to feed young turtles 1-2 times a day. And older individuals, after they turn 2 years old, can be given food every other day.

A turtle's diet must contain foods enriched with calcium. This could be eggshells, bone meal, chalk. It is recommended to add special vitamins for reptiles to the food. They can be purchased at any pet store.

Hygiene rules

Marines require regular care for their claws. It is recommended to trim them regularly, but this should be done with special devices, and not with ordinary scissors. In this case, it is very important not to affect nearby blood vessels. But under no circumstances should the beak be trimmed. With its help, the turtle copes with pieces of meat during lunch.

Major diseases

Of all the diseases found in these animals, the most common is pneumonia. Sea turtles do not tolerate drafts very well and can catch cold easily. When observing the first signs of illness (lethargy, refusal to eat), it is necessary to begin treatment. This should only be done under the guidance of a veterinarian and should not be self-medicated under any circumstances. An experienced specialist will correctly prescribe medication treatment. In addition to this course, you can prepare a steam bath with chamomile infusion for your turtle. The steam should be at such a temperature that it does not burn your hand. After holding the animal over the steam for a while, then place it for an hour in a warm bath, one-third consisting of chamomile decoction.

Discharge from the eyes, swelling of the eyelids, soft shell - all this is a serious reason to contact a veterinary hospital.

If you decide to have such an unusual pet at home, you should keep in mind that under favorable conditions, a turtle can live up to 35-40 years.

General characteristics.

sea ​​turtles belong to the class of reptiles of the turtle family (Testudines) of the superfamily (Cheloniidae). Science has proven that they appeared in nature more than 220 million years ago. Sea turtles are classified into families, subfamilies, genera and species. In total, there are 6 species of sea turtles, which are grouped into 4 species of one family (Cheloniidae).
Until now, zoological scientists do not have a consensus on their classification. Some classify turtles as a subclass of parareptiles, and some even try to separate them into a separate class. That is why in this article we will not dwell on this topic in detail.

Habitat.
Sea turtles live mainly in tropical seas and in warm currents of the Atlantic, Pacific and Indian oceans. However, cases of their appearance have been recorded in the cold waters of the Barents Sea and in the Far East. And this is not surprising, because sea turtles are excellent swimmers and spend most of their lives in the water, easily covering thousands of nautical miles. On land, they choose mainly for mating and laying eggs.

Physiological characteristics of the sea turtle.
A characteristic feature of the structure of sea turtles is their horny or bone-horny shell, which covers the main part of their body, performing the function of passive protection.
The carapace consists of strong dorsal and ventral shields called the carapace and plastron, respectively. Unlike their land relatives, sea turtles do not have the ability to retract their heads and limbs into their shells.
In addition, life in the water element has transformed their limbs into peculiar flippers, which are pronounced in large turtles and less so in small ones, and in some species, there are only swimming membranes between the fingers. The forelimbs of turtles are more developed than the hind limbs, which allows them to maneuver well in water and reach speeds of up to 35 km/h, which, given their rather large size, is a very good result. The jaws are completely devoid of teeth and covered with strong horny plates, reminiscent of a beak in shape.
The main food for small sea turtles is zooplankton and nekton, and the diet of large turtles includes small jellyfish and various crustaceans, although with age they prefer to eat exclusively plant foods (sea grasses, limnophilic algae and elodea), which are obtained in deep coastal waters more than 10 meters.

Sea turtles are quite large in size. The green sea turtle is considered the largest in their family, the maximum weight of which can reach 200 kg, and the length from head to tail is more than one and a half meters. The size of the turtle shell of such turtles varies from 80 to 120 cm in diameter. The record holder, listed in the Guinness Book of Records, is a leatherback turtle, whose length was about three meters, and it weighed almost a ton - 916 kg.!!!
The smallest representative of its relatives is the olive ridley sea turtle (Lepidochelys olivacea). Its weight usually does not exceed 50 kg, and the diameter of the shell is 50-70 cm. In terms of size, all other species of sea turtles occupy a niche between the two above-mentioned species.

The place for sea turtles to lay eggs is the islands on which they were born. Scientists have not yet come to a consensus on how they find these islands, located several thousand miles away.
According to one version, turtles orient themselves in space using the earth’s magnetic field, but there is still no significant evidence confirming such a theory.
For example, the Atlantic ridley, which lives in the waters of western Florida and the Gulf of Mexico, constantly migrates from these along the coasts of Venezuela, Morocco, Cameroon, and young individuals are even found in the territorial waters of the Netherlands, Spain, France, Belgium, Ireland and Great Britain. However, it has been established that it breeds (lays eggs) only on one single beach in the Gulf of Mexico.
Sexual maturity of female turtles occurs at approximately the age of 30 years, after which they come to land every 2 or 4 years, dig deep holes and lay in them from 150 to 200 eggs, the size of a chicken. Moreover, in order to preserve offspring from various predators, turtles make 4-7 such clutches. Incubation period from the moment of laying eggs to the appearance of offspring is 50-70 days.

The average lifespan of sea turtles is 70-80 years.
Since ancient times, along with natural disasters, the main enemy of sea turtles has been humans. That is why many species are now on the verge of extinction. Turtles themselves were also used as food (the famous turtle soup) and turtle eggs, which are high in calories (155 calories per 100 grams) and contain various useful minerals (iodine, iron, magnesium, potassium, calcium), as well as vitamins A, E , D and B.
And although the situation has recently begun to gradually change for the better, more and more often certain species of turtles are listed in the Red Book and taken under protection by government agencies in many countries and various animal protection organizations.

Sea turtles are, without a doubt, one of the most mysterious animals on our planet. Their mysteries do not lie in appearance or speed of movement, and in the characteristics of behavior, in their migrations and ability to find the right place in the ocean or return to their “home” - the beach on which they were born, which is also called homing. This has baffled and continues to baffle both scientists and all those who come into contact with sea turtles. Through the efforts of researchers, much has become clearer, but complete knowledge is still very, very far away. Let's talk about it.

About sea turtles

First, about the turtles themselves. There are five species of sea turtles: the most famous green turtle, hawksbill turtle, ridley turtle, loggerhead turtle and leatherback turtle. The turtles' legs turned into flippers, and they themselves became excellent swimmers and divers.

When Columbus moved towards the New World, his caravels encountered such large flocks of turtles at sea that the animals had to be literally pushed aside, and this caused amazement to the Spaniards. In honor of the discovered clusters, Columbus named the Turtle Islands he encountered; now these islands are called the Cayman Islands, especially since turtles were caught there not even a hundred years after their discovery.

Green sea turtle

Columbus encountered primarily the green turtle in large numbers. Its shell is 120-140 cm long, its weight reaches 200 kg, and in very rare cases - up to 400 kg. It is important that the history of the further discovery and development of the New World is closely connected with sea turtles and, above all, with green turtles. The fact is that they are a great, high-quality food, and they are much easier to catch than fish. They were also called canned sea food - it is enough to turn the animal on its back and it becomes completely helpless, while, unlike fish, it can live for a very long time on land or on a ship. Turtle eggs are excellent and nutritious, and gourmets value the taste of meat and especially turtle soup above everything else. It’s not for nothing that the famous turtle expert, American scientist Archie Carr called the green turtle “the most useful reptile in the world.”

Therefore, almost every ship that found itself in the Caribbean or off the coast of North and South America first of all filled its holds with green turtles, reliably providing itself with delicacies. Now the sailors could forget the stinking corned beef and moldy crackers for a long time.

Eggs laid by females were dug up on beaches by the millions. To leave offspring, the female green turtle goes to the beach at night, digs out a pitcher-shaped nest about 20 cm deep with her hind legs and lays there up to 150-200 eggs in a leathery shell, the size of which resembles table tennis balls. Neither the bright light of lamps, nor the presence of people, nor extraneous sounds can distract her from this most important matter in life. In water, in zero gravity, a turtle moves extremely easily, but on the beach the force of gravity falls on it and presses it into the sand. Every step comes with great difficulty.

But now the eggs are laid, she fills the nest with sand, levels it with her weight, crawls and tries to camouflage it. It often happens that she digs one or two false holes, but does not lay eggs there. The whole night passes in exorbitantly difficult troubles, and only after completing its duties does the turtle crawl into the water. God forbid she stumbles in some pothole or on a lying snag and rolls over - then she is doomed to death. Her efforts often do not save the eggs from predators - ocelots, jaguars, coyotes, stray dogs, raccoons, snakes that dig up nests and are literally on duty on the beaches at such times.

As has always been the case, the most terrible predator is man, and through his efforts, the number of green turtles not only off the coast of America, but also throughout the tropical zone has sharply decreased. Where there used to be tens of thousands of them, hundreds remain, and in many places they have disappeared altogether. The green turtle can be considered to have completely disappeared from Bermuda, the Greater Antilles, the Bahamas and many other Caribbean islands. The same fate befell it, and, by the way, other species of turtles on the southern coast of the United States, almost everywhere on the shores of Africa, Southeast Asia, Sri Lanka, Borneo, Sumatra, Madagascar, and Australia.

The whole history of sea turtles is a typical, more than once encountered case when a person thoughtlessly, without regard for anything, chopped off the branch on which he was sitting. There are enough such examples among marine animals, take at least Steller's cow, which could have become an ideal pet, but it was destroyed after discovery for 27 years. In those places where turtles regularly swam to breed, even a profession arose - egg collectors. And the chain of existence of animals is easy to break at the most vulnerable link. It’s also good that there were scientists who assessed the scale of the impending disaster and sounded the alarm. Their efforts were not in vain: a number of sea turtle breeding sites are now protected.

All sea turtles have long been hunted with nets and harpoons from boats, which, along with digging up eggs, has greatly reduced their numbers. There is also such a way - they take a sticky fish, on the tail of which there is a ring with a long cord, which they throw into the water when they see a swimming turtle. Sticky loves to stick to some large animal in order to go on a trip with it for free, which she does when she discovers a turtle. The fish's suction is so strong that all that remains is to pull the turtle towards the boat by the cord.

Hawksbill turtle

The smallest is the hawksbill turtle, or carriage turtle, which has the most beautiful shell, which was its misfortune. Even in ancient times, expensive translucent jewelry was made from the hawksbill shell - combs, brooches, boxes, earrings, beads, as well as buttons and many trinkets. Prices were always very high and the larger the product, the more they asked for. There is information that the Roman Emperor Nero, who considered himself a brilliant actor, had a favorite tortoiseshell bath of extraordinary beauty, which can probably be considered the largest product made from hawksbill shells. However, hawksbill meat and eggs have also always been popular. In a sense, the hawksbill was saved by the invention of plastics: the extraction of their shells ceased to be widespread. However, fashion can turn towards natural products at any time.

The hawksbill is widespread throughout all tropical seas; it has a tendency to wander and, in addition to the Atlantic, is common in the Pacific and Indian oceans. It happened that she even ended up off the coast of England or the northern states of America. And in all places, naturally, it was the subject of hunting.

Loggerhead sea turtle

The loggerhead is also called a false carriage, it is similar to the hawksbill, but larger, and the shell, fortunately for the animal, is not suitable for crafts, the meat is not considered tasty, but the eggs are collected as actively as those of other turtles. Therefore, the number of loggerheads is falling on the coasts of South Africa, Australia, and the Caribbean.

Ridley turtle

The ridley, or olive turtle, has long been a mystery, because the Pacific subspecies lives in the Pacific and Indian oceans, the breeding sites of which are well known, but no one knew about those of the Atlantic ridley subspecies. A. Carr spent many years on the riddle of the Atlantic Ridley before he solved it, about which he wrote an interesting book. After a long and thorough search, it turned out that Atlantic Ridleys come to the beaches to lay eggs, gathering in giant flocks, only once a season, in the spring, and in just one or two places along the Gulf Coast. In this case, you need a strong wind to blow and the sea to be rough. It was possible to guess the date of the release and the place almost by chance, but it still happened - on a remote deserted beach, indicated by local residents, where for twenty-four days in a row a small plane was cruising with a cameraman eager to film the “arribada” - a mass exit of female turtles, there was nothing.

The operator eventually lost faith in filming anything and did not fly on the last, twenty-fifth day. Then his place in the plane was taken by another person, who flew simply out of curiosity, but, fortunately, took a movie camera, and on that day he filmed a miracle - the same beach, but filled with thousands of ridleys who came out to leave offspring. It was truly possible to walk more than a kilometer along the beach without stepping on the sand, but only walking on turtle shells. Carr estimated the number of turtles that arrived at the arribada at forty thousand!

The film made a strong impression on scientists, and indeed on everyone who watched it, and in Carr’s opinion, the man who shot it “is more than worthy of ennoblement, a Nobel Prize or any other honorary award.” The mystery of the Atlantic Ridley has been solved. Scientists first saw the scale of its reproduction at that time, of course. It was also difficult to do this because on such a day, ridleys often go to the beach along with other turtles, for example, loggerheads, which they are very similar to, and disguise themselves as the latter. Carr worked with other conservationists to protect the nesting sites of Atlantic ridley and other turtles.

Leatherback turtle

The leatherback turtle is the largest of the sea turtles, its shell length reaches 2 m, weight - 600 kg, and the span of its front flippers is more than 3 m. It can be compared to a battleship among its relatives, and also fast, since it is an excellent swimmer. The leatherback turtle's element is the open tropical spaces of the ocean. It is not safe to hunt such a giant; there have been cases when turtles have bitten oars with their powerful jaws, and broken the side of a boat with a blow from a flipper. And she dives better than other turtles. A wounded leatherback turtle emits a loud cry, reminiscent of a dull roar or moo.

The shell of a turtle is covered with skin, for which it got its name, and both the skin and the shell are richly saturated with fat, which, after rendering, is used to coat the seams in boats. This feature complicates the storage of museum exhibits, because fat oozes from them for several years if not taken care of.

The leatherback turtle does not form schools and is most often found alone, and also goes to secluded beaches to lay eggs. Despite its widespread distribution, no more than four or five breeding sites are known on the coasts of Africa, South America, the Malay Peninsula and Central America. She was observed twice in our waters - in the Bering Sea and in the south of the Far East, that’s where her wanderings took her! She digs a hole for eggs to match her size, up to a meter deep, eggs the size of a tennis ball. With her weight she compacts the filled nest so much that it is almost impossible to get to the eggs. The lifestyle and migrations of this huge turtle have been little studied in comparison with its relatives.

After about two months, tiny turtles hatch from the eggs in the heated sand, which in a green turtle are no more than 5 cm long. But they are very lively, which helps them destroy the sandy roof of the nest and get out. Instinct kicks in and the turtles rush as fast as they can towards the sea, the direction to which they determine by the light reflected from it. Having time to reach the water is a matter of life, because predators, joined by crabs and birds, are already on duty on the beach in full force. And they're prowling in the water predatory fish. The only thing that saves us is the simultaneous emergence of numerous turtles, which most often run to the water at night. But it happens that out of hundreds, only a few make it to the surf.

In the water, turtles immediately develop top speed, swim in zigzags and dive at lightning speed when they see a large shadow approaching. This is how instinct saves many from seabirds. It is important to move away from the shore. And then their paths go into the unknown.

This unknown is the main aspect of the life of sea turtles. In recent decades, people have just begun to understand it, and tags have helped a lot. How to tag a turtle in order to further trace its migration routes? It would seem simple, but at the same time not quite. Well, let's say, catch or use the moment of laying eggs, make a small cut in the shell and release. Convenient, but what will it say to those who catch it? In addition, turtles often rub against coral reefs, tearing off fouling and damaging their shells on the sides. For the same reason, a tag made of stainless material, which was attached to a wire threaded through a hole in the shell, was rejected. But it is desirable that the mark remains for many years during the animal’s wanderings. They also used the following mark: a hinge was embedded in the edge of the shell, to which a cord 15 m long was attached with a bright buoy at the end. The cord did not prevent the turtle from diving, and if an orange balloon was attached to the buoy, the turtle was detected from a great distance. Then they came up with the idea of ​​attaching a radio transmitter to the shell or even to the ball, and the turtle calmly carried everything around with it. But such tags worked at a relatively short distance and required power.

Perhaps the most reliable were small plates firmly attached to the shell. They, basically, brought scientists information that they sometimes refused to believe. Here is an actual case - a hawksbill, ringed by a Dutch officer in 1794, was caught on the same beach 30 years later. Scientists heard some incredible stories that were sometimes told by turtle catchers.

So, the lucky tiny turtles disappear into the vastness of the sea. We know very little, almost nothing, about the subsequent period of life, which will last several years. There will be thousands of kilometers of sea routes, all kinds of dangers, until the time comes to reproduce. And now a powerful instinct tells the big turtle to swim steadily towards his “home”, to the beach where he once got out of the sand. Well, how do you know which side is “home”, which direction to choose? And the turtle, being from “home” even thousands of kilometers, unerringly chooses the direction. How does she do this, what guidelines does she follow? We don't know, we can only guess.

Scientists have considered various hypotheses. Well, let's say, visual orientation, when hills or individual mountains on the coast can serve as noticeable points and landmarks. It was calculated that a turtle, which swims on the surface of the sea and can only raise its head very low, in the best weather could see them at most a hundred kilometers away. What about the other thousands that need to be overcome?

The bottom topography also cannot be a guide - turtles do not dive deeper than 20-30 m, they have nothing to do there, all food is at shallow depths. It is also incredible to navigate by acoustic signals in the ocean, say, by the sound of the surf or by the deafening, audible from afar, crackling of click crayfish that inhabit every crevice in the reefs. It was suggested that turtles could navigate by the Earth’s magnetic field, but this hypothesis did not stand up to criticism: not a single structure or organ with magnetic sensitivity has yet been found in turtles. They also came up with another possibility that is hard to believe: what if a tortoise, from childhood, remembers all the turns of its long-term routes, all the landmarks that it came across? There were also more serious suggestions to attribute to turtles the “sun-compass” and “star-compass” orientation characteristic of birds and other animals. But here we get very big stretches - now we’ll see what, despite the fact that turtles, like birds, have precise biological clocks.

Let's consider them using the example of the small Ascension Island, located in the equatorial Atlantic Ocean more than 2000 km from the coast of Brazil, almost halfway between South America and Africa. Green turtles, having emerged into the light on the beach of this island, must, in order to survive, swim to places where there is a lot of food, because they cannot get much food near their “home.” And they set a route towards the coast of South America, and here the Equatorial Countercurrent helps them. For several years, as the tags showed, they carelessly feed off the coast of Brazil, Venezuela, and sometimes swim into the Caribbean. But now the time comes to return to our home beach.

But how can a green turtle get to Ascension Island, lost in the ocean? Only there will she be able to lay eggs and leave offspring. And she takes this most important route in her life. Excuse me, but how does she choose the direction, what is she guided by? After all, in front of it are gigantic layers of ocean water with a length of more than two thousand kilometers. This doesn't bother her. She swims and if you mark her path on the map, you can see that she is following a certain direction. She is carried out of the path of the current, overwhelmed, covered, turned around by waves and incoming squalls, but the day after that she stubbornly returns to her route. Of course, she sees the sun, but it's hard to imagine how this can effectively help her, given her situation. If only she were a bird flying at an altitude of two to three kilometers! And here there are only waves around...

But the genus of turtles on Ascension Island, apparently, would have ceased if the instinct fixed in thousands of generations had not worked, and would not have steadily led our turtle, thanks to homing, to the desired goal - the “home”, which she saw only once in her life at birth. After several weeks of sailing, the native island appeared on the horizon. The turtle completed his task, which makes finding a needle in a haystack seem like child's play.

This seems incredible from the point of view modern development navigation. Having again gone through all the hypotheses expressed earlier, Carr expressed his own - the turtle finds its native island, guided by smell. But where does it come from? Two circumstances were taken into account here. The first is that, as we said, the Equatorial Countercurrent goes to the shores of Brazil, bypassing Ascension Island. And second - a turtle, in order to fulfill the will of instinct, must have a supersensitive, fantastic sense of smell. By the way, such a sense of smell is not uncommon in the animal world; insects have it, reacting to literally dozens of molecules of the smell of a sexual attractant. or migratory fish, for example, salmon, returning by smell to their native rivers and streams to leave offspring. Apparently the turtle has it.

Moving through the ocean water, the turtle swims towards the countercurrent, capturing tiny concentrations of the “native” smell that was forever imprinted in its brain when it was born. She always tries not to leave the “wedge of smell”, which becomes stronger as she approaches “home”. It’s hard to imagine, but at such distances the turtle unerringly finds its target.

In putting forward the hypothesis, Carr emphasized that no other one could simply explain this phenomenon, and he would willingly consider and accept any other point of view if it was accompanied by convincing evidence. This hypothesis could hardly be true, for example, for Pacific turtles, when there may be no currents near their “native” beaches, and turtles are able to arrive at them from different directions.

But sea turtles are also capable of presenting other mysteries, the solutions to which are not yet really visible.

Early one morning in the Caribbean, turtle catchers were checking their nets near a coral reef. During the night they brought back a catch - a large green turtle was entangled in them. When the turtle was dragged into the boat, the surprise of the eldest of the catchers knew no bounds: on its shell he saw a mark that with my own hands cut out a few months ago. But then the turtle was caught here and sent on a schooner to Florida, to please lovers of turtle soup some time later. What happened? The tagged turtle arrived on the shores of Florida and was placed in a cage with other turtles also awaiting their fate. Probably, everything would have happened if a storm had not come at night, tore the cage and the turtle was free. Wasting no time, she went to the bay where she was caught and where there were such good seaweed pastures. But excuse me, what do you mean gone? How did she know where to go? After all, they transported her on a schooner upside down on the deck and covered with other turtles with a tarpaulin. The eldest remembered this with absolute certainty. And what could you remember, even if you wanted to, when there are only endless waves around? If you look at the map, then from the cage to the place where she was caught, the straight line is about 1,500 km. Just. The turtle, of course, could not swim in a straight line; it had to stick to the banks in order to feed in shallow water. In addition, a straight line passes through the western tip of Cuba. sea ​​turtles do not move on land. This means that her path lengthened greatly.

The main thing in the riddle is that at every turn of the coast, when passing every cape, the turtle knew exactly where to turn so as not to lose the right direction, although it was the first time in its life that it swam along such a route. Several times she encountered currents, sometimes very strong ones. They tore her down, but she persisted in making adjustments and getting back on track. She knew exactly what distant point of the sea she needed to return to, no matter how incredible it may seem to us!

The difficult and long journey ended with her arriving a few months later at her favorite pastures in that bay, where she had a second meeting with the catchers. No wonder that first of all they did not believe their eyes!

These reliable cases, as well as others told by catchers, made scientists who studied the navigation abilities of animals think. They decided to experiment. The green turtle was caught, tagged and taken 600 km away. And what? 12 days later she was again swimming peacefully in the same bay. Marks were added to the information - often the impression was created that the turtles were marked when they purposefully swam along some route known only to them and immediately after marking they continued. How else can we explain that they managed to swim a very long distance in a relatively short period of time when they were caught again?

It also happened that the same turtle was caught, marked and taken hundreds of kilometers away - it returned, it was taken again now in a different direction, the same thing was repeated, taken in a third direction - with the same success. And the important thing is that each time she returned not to her native beach or favorite pastures, but to that point of the sea that was unremarkable for her, where meticulous scientists interrupted her route, and each time, finding herself in the distance, she correctly determined her position on the open sea and knew exactly where to go.

Truly eternal wanderers, sea turtles feel completely free in the vast expanses of the ocean. One can only conclude that they know much more than we do about the sea and have methods of navigation that we have not yet imagined. And Carr’s very interesting and possibly correct hypothesis of “smell guidance” only works when returning to “home,” during homing, and perhaps in some cases when conditions contribute to this.

Text: Alexander Tambiev (Professor, Doctor of Biological Sciences, member of the Writers' Union of the Russian Federation)
Photo: V. Zverev, A. Aristarkhov, A. Samarin

Archived article from No. 3 (33) for 2004.