The underwater world of Mu Ko Surin National park. Photos of sea turtles - sea turtle habitat Where are sea turtles found

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 the 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 his life 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 is obtained in coastal waters at a depth of 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. The 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 government agencies many countries and various animal welfare organizations.

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Sea turtles are reptiles of the turtle family, which includes 5 genera.

Turtles live in warm waters Indian and Pacific Oceans, as well as the Atlantic. These animals are tireless swimmers, spending their entire lives in the water. On the shore, turtles are slow and only go there to lay eggs.

Sea turtles choose small islands, lost in the vast waters of the ocean, as places to procreate. However, animals unerringly find pieces of land, swimming vast distances. Scientists have put forward many hypotheses commenting on how they manage to navigate the water perfectly. One hypothesis is that sea turtles may use magnetic field land.

Structural features and sizes of turtles

All sea turtles are quite large creatures. The largest in the family is the green sea turtle, whose body length is 1.5 meters and its weight ranges from 80 to 190 kg.

The length of the shell of such a turtle is 80-120 cm. There are very large representatives of this family, whose weight exceeds 300 kg. The largest turtle that scientists were able to measure had a shell length of 153 cm and weighed 395 kg. Small representatives of this family also live in nature.

Sea turtles are large reptiles.

The smallest turtle is the olive ridley sea turtle. This leisurely creature weighs no more than 50 kg, and the length of the shell is 60-70 cm. Females usually weigh less - 25-48 kg. The weight of the heaviest male representatives of this species does not exceed 35 kg. The remaining species of sea turtles are between these two species in size. What unites all members of the family is that the limbs in the form of flippers and the head do not retract under the shell.

The dorsal-ventral shell of large sea turtles is flat. The front legs, much better developed than the hind legs, are flippers. The turtle's head is large, sitting on a short neck. The head is not retracted into the shell, nor are the limbs. The shell of a sea turtle, called the “carapace,” has a bony base and is covered with horny scutes. The color of the shell varies - black, light brown, greenish.

Nutrition, population situation

Small sea turtles feed on zooplankton and small nekton, while adult turtles prefer plant matter. Despite the fact that during the mating season these animals migrate far into the ocean, their main habitat is in the coastal zone.

Sea turtles are omnivores.

At a depth of ten meters, the sea turtle finds a variety of plant food. In addition to various algae, the diet of turtles includes mollusks and jellyfish. Sea turtles attack those inhabitants of coastal waters that are even slower than themselves. This species chooses sea caves for recreation.

Since ancient times, the main destroyer of sea turtles has been man. People have always had a huge commercial interest in these leisurely inhabitants of the deep sea because of their delicious meat. Sea turtle eggs were considered a delicacy and a huge number of clutches were destroyed.

All this, along with the low survival rate of young animals, led to a sharp decline in the population of these unique armored animals. Currently, there is a ban on hunting sea turtles, however, this law is difficult to enforce in large expanses of ocean. In this regard, the population of sea turtles is not high and leaves much to be desired.

Reproduction and lifespan

Young sea turtles reach sexual maturity at 25-30 years of age. All the time before the start of the breeding season, turtles swim in the salty sea. But in the nesting year, sea turtles that have reached adulthood rush to the piece of land where they once hatched from the egg.

Having reached small islands scattered in the ocean, turtles mate close to the shore. Then the females begin to prepare the nests. They crawl ashore and rake up the sand with their hind paws. Nest holes emerge, approximately 40-50 cm deep. The female lays eggs there.

Sea turtles are long-lived.

The number of eggs in one clutch can be up to 200 pieces. Having laid the eggs, the female buries the nest and carefully compacts it so that the hole looks as inconspicuous as possible. During the year of nesting, the female makes 5-7 clutches of eggs. The next breeding season will occur only after 3-4 years.

After the female sea turtle lays her eggs, she leaves to surf the sea and does not care about her offspring at all. She is not interested in what will happen to the masonry. The period of development of turtle cubs in eggs occurs within 2 months. Moreover, the sex of hatched turtles depends on temperature environment.

If the temperature was quite low, males are born. At higher air temperatures, the eggs will hatch into females. But if the temperature change is too sharp, the masonry may die completely.

The turtle egg shell is pierced with the so-called egg tooth. The newly born sea turtle cubs rake up the sand and climb out of the nest hole. This is where the most dangerous period of life begins. They are hunted both on land and in water, and from the air. As a result, a very small number of reptiles of this species survive to adulthood. But if the little turtle cub still managed to survive, his life expectancy could be 80 years.

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sea ​​turtles- the largest representatives of the detachment. There are only seven species, grouped into two families. They live mainly in tropical and subtropical seas and oceans. Only females come ashore and only for a few hours to lay eggs. Unlike freshwater species, the shell of sea turtles is low and flattened. In the water they row with their front flippers, which are much larger than their back ones. Clumsy on land, turtles “fly” at great speed in water. While moving, turtles must come to the surface every few minutes to take in air. But while resting or sleeping, they can remain underwater for several hours. Sea turtles have well-developed organs of vision and smell, with the help of which they find food, detect enemies and find a sexual partner. Like all turtles, sea turtles have no teeth. They bite and crush food with strong horny beaks. Young turtles feed and then move on to larger food. Adult green sea turtles eat primarily marine foods. But other species prefer jellyfish, squid, shrimp, etc.
Year after year sea ​​turtles return to the same place to lay eggs. After mating at sea, the female crawls onto the beach and slowly crawls along the sand, climbing above the high tide line. There she digs a hole with her fins into which she lays eggs, 2-3 per minute. Each turtle can lay anywhere from 50 to more than 150 eggs. Next, she fills the nest with sand and levels it with her fins. Eventually, the female returns to the sea, leaving the eggs to incubate in the sun-warmed sand. She does this several more times, laying eggs in different places on the beach for about 10 days.
Depending on the temperature of the sand, sea turtle embryos take about eight weeks to hatch. The cubs are released from the shell and must then make every effort to get out of the sand. It takes a team effort for the turtles to reach the surface, which sometimes takes several days. Once on the beach, the turtles rush to the sea. Many become victims of predators: seabirds, crabs, otters, foxes, lizards. Those who do reach the water try to quickly go deeper. But here they are threatened by predatory fish.

The huge leatherback sea turtle is named for its shell, which has a dense leathery structure supported by thin bones. They feed mainly on jellyfish, which they catch and cut with their jaws, like scissors. It is known that in search of food they can descend to a depth of up to 900 m. The head of the loggerhead is quite large in comparison with the rest of the body. Powerful jaw muscles allow this turtle to crush the shells of crabs and lobsters.
Some species of sea turtles spend their lives without leaving a small area. But there are species that undertake long journeys between the areas where they feed and the place where they breed. Most green turtles belong to the second group. Some fatten in coastal Atlantic waters South America, and then sail to the tiny Ascension Island, located 1,500 km away.
The hawksbill is the most heat-loving sea turtle and is often found in shallow coastal waters around coral reefs and bays. It is one of the few large animals whose food is mainly sponges.
The front fins of turtles are wide and flat. They don't so much row as they flap their wings up and down, like birds' wings.
Living in the open ocean in coastal waters, the Pacific olive turtle is one of the smallest sea turtles. Its length does not exceed 70 cm, and its weight is 41 kg.

For a long time, turtles have suffered from human interference in their lives. People hunt them and dig up their eggs. The shells of turtles, mostly hawksbill turtles, are used for souvenirs such as combs. Today, turtles have lost many of their nesting territories - tourist centers have been built there. Conservation organizations are trying to preserve baby turtles by collecting them from protected nesting areas and releasing them into the sea.
The green turtle was exterminated in huge numbers for its meat, shell, eggs and skin. It has become extremely rare and, along with other sea turtles, is on the official list of protected animals. Trade in products made from them is under strict control.

Turtle families

sea ​​turtles
- 6 types
- Flat bony shells covered with horny plates
- Limbs converted into flippers
- Representatives: green turtle, hawksbill turtle, olive turtle, loggerhead

Leatherback turtles
- 1 type
- Leathery shell

There are 6 species of inhabitants of tropical seas. Conventionally, these reptiles can be divided into Pacific and Atlantic. But they differ little from each other, and the history of their life on Earth is similar.

Green sea turtle. general description

The largest species is the green turtle (photo below). Some giant individuals weigh about 450 kg, but, as a rule, their body weight is approximately 200 kg. The length of the low, rounded-oval carapace ranges from 70 to 150 cm. The carapace is covered with scutes that cover each other and lie side by side. The forelimbs in the form of flippers with one claw are indispensable for swimming. Large eyes are located on the small head. The carapace (the so-called dorsal part of the shell) can be olive green or dark brown with yellowish spots, its color is variable. The ventral part of the shell is yellowish or white.

Green, unfortunately, is also called soup. It is for the sake of tasty and famous meat that these animals are destroyed. Turtle hunting continues everywhere. In places where the aquatic green turtle lives, its meat is eaten and also fed to pigs. Crafts and souvenirs are made from shells. Even bone plates of lesser quality are used. Eggs are eaten fresh or added to pastries. Therefore, even if turtle meat is not exported to markets in large cities and other countries, many species are constantly under threat of complete extermination.

Reproduction of sea turtles

At the age of 10 years, turtles reach sexual maturity. Animals travel hundreds of miles across the ocean to mate. They swim to their native places where they were born. Mating occurs in the sea, a short distance from the shore.

After mating, the female digs a hole in the sand on the shore and lays 100 to 200 eggs in it. The green sea turtle covers the clutch with sand, thereby protecting it from predators, direct sun and heat. Small turtles will hatch from eggs on days 40-72. An egg tooth will help them open the shell, which will fall off in the first hours or days of life.

Having hatched, the turtles rush to get to the water, using their flippers as hard as they can. Kids, unlike adults, are very agile. This is a decisive moment in the beginning of their life, since on this path the turtles are especially vulnerable to birds, snakes, and rodents. But in the sea they are also in danger - sharks, dolphins, and predatory fish are not averse to feasting on baby sea turtles.

Construction of a pool for captivity

Contents are only possible in high-quality ones with a temperature between 22 and 26°C. Indeed, in nature, the green sea turtle lives in warm tropical seas and only comes to land to lay eggs. The size of the seawater pool must be large, since adult reptiles are large and need a lot of space to swim. The optimal shape of the pool is round; its surface should be smooth and covered with silicone.

Good filtration, and in certain circumstances, partial replacement of water to stabilize the pH value, is mandatory, due to the very intensive metabolism of sea turtles. Cleaning the pool by sucking out food debris and waste should be done regularly. Before placing new individuals in the pool, they must be inspected.

Adult reptiles are herbivores and eat algae and grass, but when they are young, turtles eat animals such as crabs, sponges, jellyfish, worms and snails. When choosing a feeding diet for sea turtles, you should pay attention to the prevention of water pollution. Thus, it is not recommended to use cod meat that is too soft, fatty herring, or lettuce. Shrimp, lean sea fish, seaweed or spinach are quite suitable food for sea turtles.

sea ​​turtles are among the most ancient creatures on Earth.

sea ​​turtles are among the most ancient creatures on Earth. Today you can find 7 types turtles, which have been around for 120 million years, are older than dinosaurs. A sea turtle's body, or "shell," is streamlined for swimming in water. Unlike other turtles, sea ​​turtles They cannot hide their paws and head in their shell. Their color varies from yellow, greenish to black, depending on the species.

Fast Facts

Size: Kemp's ridley is the smallest sea turtle at 30 inches (76.2 cm). The largest sea turtle is leatherback turtle– an adult can reach more than six and a half feet in length (more than 1.8 m). Adult females and males are the same size.
Weight: Ridley Kemp weighs from 36 to 45 kg. Leatherback turtle can weigh more than 907 kg.
Life expectancy: up to 80 years.

Diet

The diet of sea turtles depends on the subspecies, but the general diet consists of jellyfish, seaweed, crabs, shrimp, sponges, snails, algae and mollusks.

Population

It is difficult to determine the number of sea turtles because males and young sea ​​turtles, do not return to shore after they hatch and reach the ocean, making it difficult to keep track of them.

Habitat

Sea turtle lives in all warm and temperate waters around the world, and migrates hundreds of kilometers from breeding and feeding grounds. Most sea turtles undertake long migrations, sometimes swimming up to 2,253 km from feeding grounds to the beaches where they nest.

Behavior

Sea turtles spend most of their lives in the water, so not much information has been collected about their behavior. Almost everything that is known about sea turtle behavior comes from observing young turtles and females emerging from the water to lay eggs. Sea turtles, like salmon, return to the same nesting site where they were born. When the females come to the shore, they use their dorsal flippers to dig nests in the ground, bury the clutch there and return to the ocean. After hatching, baby turtles can spend up to a week digging themselves out of the nest. They emerge at night, move towards the ocean and remain there, alone, until it is time to mate.

Reproduction

Temperature: The temperatures of the sand where turtles dig their nest determine the sex of the turtle: temperatures below 85 degrees F (30º C) produce predominantly male turtles, and above 85 degrees F (30º C) predominantly produce female turtles.
Mating season: March to October, depending on the species.
Pregnancy: 6-10 weeks.
Clutch size: about 70-190 eggs, depending on the species.
When the little turtles hatch from their eggs, they head towards the ocean. Few survive and enter adulthood.

Did you know?

Green sea turtles can stay underwater for up to five hours, although foraging dives typically last five minutes or less. Their heart rate slows to conserve oxygen: 9 minutes can pass between heartbeats.

Climate change and other threats

Climate change threatens the existence of unique sea turtles, as the temperature at which eggs are incubated determines the sex of the turtle. As global temperatures continue to rise, sea turtles may experience female-only births as sand temperatures rise above 30 degrees Celsius. Climate change is increasing the severity of coastal storms and is also contributing to sea level rise as Arctic ice melts. Stronger sea storms and rising sea levels will destroy sea turtle nesting sites.
Sea turtles are threatened by coastal development, extensive turtle and egg markets, pollution and pathogens, global warming, and fishing. Fishing is considered one of the leading causes of death and injury to sea turtles worldwide, and turtles have been known to bite baited hooks, become entangled in lines, or be strangled by dredges.
Defenders wildlife are working with partners to protect coastal beaches used as nesting sites by sea turtles and are asking beachfront homeowners and hotels to dim their lighting to avoid disrupting sea turtle nesting seasons. Advocates are also working to ensure that fisheries around the world use fishing methods and gear that are safe for sea turtles.

Legal status / Protection

Endangered Species Act: Six of the seven species of sea turtles are protected under the Endangered Species Act.
IUCN Red List: Three species are listed as critically endangered, two are considered endangered, and one species is considered vulnerable.
CITES: All species of sea turtles are listed on Appendix I.

Reasons for hope

Luckily, sea turtles are one of the best protected animals by law. All sea turtles are listed on Appendix I of CITES. Six of the seven species of sea turtles are protected under the Endangered Animals Act.
Volunteers and trained professionals are a great asset to sea turtles. They do everything from monitoring turtle hatchings to making sure the hatchlings make it to the sea, moving eggs to deeper, colder layers to ensure an appropriate proportion of male births. Many seaside towns also take pride in doing their part to help turtles by putting bags on their lights to keep baby turtles from being lost, turning off lights during hatching periods, and closing and protecting all areas of beaches where eggs are laid.

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