Has a crocodile. When were crocodiles found in Russia? Baby Nile crocodile - survival of baby crocodiles
Crocodiles have been on our planet for about 250 million years. They were able to survive many of the most ancient animals, including even dinosaurs, and were able to endure all the changes in living conditions that occurred during this time on Earth.
Over time, these reptiles began to represent large species of amphibian predators, which frighten with their appearance, but at the same time arouse special interest. You can find out where crocodiles are found by reading this article.
So there you have it, some interesting facts that differentiate crocodiles from alligators. If you are ever unlucky enough to have someone come to you, I hope this article will at least help you identify your attacker! He waves a cloud of mosquitoes and swings his big rubber boot over the side of the boat.
Crocodiles fought with gladiators
The warm center is filled with eggs. Every summer, as the alligator project manager for the Department natural resources South Carolina, Rhodes collects hundreds of alligator eggs and incubates them under the puzzled eyes of hunting dogs in the shade of his backyard live oak tree.
These amazing crocodiles
Crocodiles are considered the most highly organized reptiles among others of their own kind. Allows us to consider them such animals, especially the nervous, respiratory and circulatory systems. Currently, 21 species of crocodiles live on our planet; they are representatives of three families: alligator, crocodile and gharial.
The alligators seem to be trapped in an ancient and meaningless way of life. “They don’t do anything,” Rhodes shrugged. They are cold-blooded, so they sit in the sun to warm up. They heat up and they crawl into the water and cool down. here in front of dinosaurs and with dinosaurs.
Now, protected by state and federal laws, alligators are returning, swimming on golf courses, splashing in backyard pools and devouring the occasional family pet. They are finally recognized and managed as ecological, economic and aesthetic resources.
Crocodiles are closely related to the long-extinct dinosaurs; they outlived them by 60 million years. years. Reptiles increasingly began to adapt to the aquatic predatory lifestyle. These animals reproduce by laying eggs. Crocodiles live 80-100 years, becoming “adults” at 8-10 years.
Why do crocodiles last so long?
For many millions of years in a row, crocodiles were inhabitants of the tropics and subtropics. Since the habitat remained largely unchanged, they also remained unchanged. In those prehistoric times, after the extinction of dinosaurs and other predators, crocodiles became the rightful masters of their place of residence. There are no more enemies left.
Moreover, scientists are increasingly citing alligators' "remarkable sensitivity to environmental poisons" as evidence that they may serve as early warning clocks for humans. Scientists have found, for example, that environmental estrogens-containing pesticides can disrupt the endocrine system of male alligators and make it difficult for them to reproduce. “Are there human consequences?” - asks University of Florida zoology professor Louis Guilette. "We don't know, but we better start finding out."
Predatory animals such as tigers, lions and leopards lived in a completely different environment and did not have the opportunity to hunt crocodiles, full-fledged inhabitants of water bodies. But, at the same time, these reptiles have a new terrible enemy, one might say - mortal. This was a man who destroyed them for two reasons:
- Fear of a predator;
- Crocodile skin is valuable in the manufacture of leather products.
- Meat and eggs - in some countries, people have begun to eat reptile meat and eggs.
There is no hunter who would not dream of getting such an amazing trophy as a crocodile.
Alligators evolved their thick skins, heavy tails and long rows of teeth in a swampy, dangerous, prehistoric world where armor was available. Only 10 percent of alligators go extinct to measure 4 feet in length. But then they are “free to go home unless hit by a car or shot.” And yet, Lang says, when you look at how alligators are sexed, you might think they were extinct centuries ago.
Cold or extremely hot nest temperatures produce females, while temperatures in between favor males. One nest may hatch mostly females, while another nearby may hatch mostly males. Or the temperature can be varied within a single nest to produce males in the center and females near the edges. "We demonstrated that sex ratios change from year to year, depending on weather and local nesting habitat," says Lang. Lang suspects that temperature-determined sex is linked to other environmental features in crocodiles that increase their chances of survival.
Where do crocodiles live?
Children, seeing this terrible animal for the first time, ask the question: “Where do crocodiles live?” Everyone thinks that sharks are the most dangerous in the sea, and only a few know for sure that crocodiles are also dangerous in the sea. These reptiles are found not only in freshwater bodies of the tropics.
For example, do birds and mammals have fixed energy requirements? the creature feeds or dies. But a cold-blooded animal can change its performance and regulate its body temperature to a state. “It can warm up, eat quickly, digest, grow, eat more,” Lang says. Or, if there is no food, a cold-blooded animal can simply shut down, lie there for months and do nothing, and still survive.
The most common myths about crocodiles
Evidence suggests that nest temperature influences other crocodilian traits. Can excessive heat, for example, cause birth defects? embryos incubated at high temperatures emerge with a curling tail and an extremely bulbous skull, which Walt Rhoads calls a "helmet head". Lang discovered that crocodile incubation temperature can later determine growth rate and behavior. In India, he said, we found that mugger crocodiles incubated at higher temperatures grew faster and produced eggs earlier than genetically identical hatchlings from the same clutch incubated at lower temperatures.
Some representatives of toothy giants can live in salt water. There are predators who express a desire to fish in coastal sea waters. These are Nile and African narrow-snouted crocodiles. Of course, rivers and swamps are considered their permanent habitat, but they are often found near river deltas, and there the water is no longer fresh at all, but brackish.
If his ability to succeed with juveniles and adults is heavily influenced by his embryonic experience, he may be more able to cope later by responding to an environmental cue, such as temperature, in a more adaptive way. For example, low temperatures may result in a tougher animal or high temperatures for rapid growth. Make these faster growing animals male and they will be larger and have the advantage of breeding.
As Lang and other researchers learn more, they uncover clues that may help solve one of the greatest scientific mysteries of all time: what killed the dinosaurs 65 million years ago? Until recently, many scientists believed that nest temperature determined the sex of dinosaurs, as it still does for many surviving reptiles. Some researchers have even suggested that this led to their demise: the climate became cold, dinosaurs produced all men or all women, and the species could not survive.
Sharp-snouted crocodiles, which are listed in the Red Book, live in the waters of mangrove shores and seashores; brackish water bodies are suitable for them. Adults sometimes swim into the open sea. The habitat of this saltwater crocodile is Central America, Mexico, Cuba, Peru and Ecuador, as well as Haiti and Jamaica.
Crocodiles have invaded Australia
How are people not afraid to live next to such monsters? But crocodiles are an integral part of Australian romance. Probably everyone knows a crocodile named Dundee. Over the past decade, a strong litter of crocodiles has been observed in tropical Australia, where they have comfortably settled in northern Queensland.
But if this is true, why wouldn't crocodiles suffer the same fate? This suggests that there was something else in dinosaur behavior or biology that made them susceptible, says Lang. Scientists say water may be part of the explanation, says Perran Ross of the crocodile specialist team at the Florida Museum of Natural History. When dinosaurs went extinct, many of the creatures that survived? including turtles and crocodiles? were aquatic. And the water they lived in may have ameliorated the effects of any large, land-dwelling animals killed. “Whatever the influence of dinosaurs on meteor impacts, global winter, etc. Perhaps it was less intense in aquatic environment" says Ross.
Their habitat is the rivers of Australia, into which sea water enters during high tides. In order to find other habitats, representatives of the largest breeds of crocodiles found in Australia swim into the ocean waters. So, while on the beach, you may have the opportunity to meet one of them.
The calmest alligator
Lang agrees that water could be a factor, but for a different reason. Alligators, turtles and crocodiles have always been attached to water, just as they are today. For animals that don't live in water, Lang says, being warm-blooded is more of an option and "another lifestyle is possible." So, like other scientists, it is possible that dinosaurs did not have cold-blooded reptilian biology at all.
In contrast, animals with high metabolisms must eat a lot. If global winter had enveloped the Earth, Ross speculated, "Perhaps the crocodiles just drowned it and all those high-speed dinots starved to death." "The long-lived nature of crocodiles would help." It doesn't really matter which sex is offspring from the same crocodile's nest - all men, all women, some of them, Ross explains. The female crocodile can live from 30 to 60 years and nest 15-45 times. As long as she gets her life right, then there is no problem.
Crocodiles living in salt waters are very dangerous animals. They cause several deaths in Australia every year. Crocodiles change their terrible teeth, 60 in number, hundreds of times during their lives.
Even a toothless, very old crocodile poses a mortal danger. He can slam his jaws shut with a force that can be measured in a ton. He easily breaks the body of his chosen victim. Small prey is swallowed whole. If the piece is too large, the “old man” calls his girlfriend for help. Very interesting fact– Crocodiles can live a whole year without food. Only after this it is better not to catch his eye!
Its genes are passed on and the species survives. He suggests that what happens in one year may not be decisive. In studies on long turtles, some beaches are believed to produce 100 percent of one sex, notes Valentine Lance, Center for Endangered Species Reproduction at the San Diego Zoo. "But a different beach may produce a different sex, or in other years there may be a mixture."
Having just flown to South Carolina from North Dakota, Lang is slumped in a chair on Rhodes' screened porch, surrounded by plastic chirping bins of newly hatched baby gators. For the past week or so, Rhodes has been monitoring the temperature of the eggs, smacking them when they got too hot, covering them with a tarp when the nights got cool. Now he has placed hatching bins on the porch of his log home, and Lang has sex with the chicks. They are "about 9 inches long", black and green with yellow stripes, and they look cheerful with small noses.
The heart of a crocodile, compared to other predators, is considered the most complex, and its brain is very small, the size of a walnut. Residents of Australia joke: “For life to last a million years, you need to be like a crocodile - have the same huge mouth, tiny brain and many girlfriends.”
Saltwater saltwater crocodile
The warm waters of India, Indonesia, and the Philippines are home to the world's largest reptile, the saltwater crocodile. But the most favorite place habitat of saltwater crocodiles - the coast of northern Australia. Some individuals were found very far from their permanent places of residence, for example, in Japan. They are about 7 meters long and weigh 2 tons. This predator is even larger than the polar bear.
One squirms as Lang picks it up, presses it lightly against the side of the bunker to get rid of excess water, and spreads eagles into the light under his large magnifying glass. He leans towards the lens and squints. “Woman,” he says. Rhodes takes another baby, measures it against a tape nailed to the table, and weighs it in a plastic soda cup resting on a scale. He then passes the squeaky Gator to graduate Lisa Davis. Rhodes collects eggs from 20 to 50 nests each year, but he doesn't know which mother laid the eggs or which father was the father.
At first glance, very clumsy saltwater crocodiles are capable of participating in long water crossings, while using their cunning: a massive body provides sea currents, which easily transport it sometimes over distances of hundreds of kilometers. By swimming through the water without any effort, predatory seafarers save their energy.
She digs the baby out with a needle and extracts the blood. same nest area? From research in Louisiana, Davis knows that some paws have two or three fathers. It's always like that? Are these the same men or different? Davis must collect excrement from his nests and hope that it contains enough epithelial cells.
“There's still a lot we don't know,” Lang says. An early suggestion was that temperature might have a mediating effect on hormone and hormone receptor levels, but this research was a success and Lance now says he's looking at the molecular level: "We still don't get it." One thing Rhoades and Lang learned is how widespread alligator sexual behavior can vary from year to year. They use this information to predict population and distribution.
Huge marine reptiles often attack humans, appearing in unexpected places. In Australia, more people suffer from crocodile attacks than shark attacks. But accurate data on attacks by these ancient predators on people is available only in developed regions of Australia. If you believe the data, then in forty-two years the number of deaths due to crocodiles is 106 people. At this time in Malaysia, attacks by fanged reptiles on people end tragically about 100 times a year.
But their work may have even more direct benefits for humans because alligators, at the top of the food chain, are indicators. If we follow them over many years and see that something has changed regarding the sex of the alligator, then we will know that it could be something in the environment, says Rhodes, and something in the environment can affect people too.
"If we have a problem with alligators, we have to look for a problem with humans," Guiletta says. Will it be the same? No, we have different mechanisms for determining gender. But phallic development in alligators depends on testosterone, and the same thing happens in a boy's body.
There is no evidence that there have been cases of saltwater crocodiles attacking people outside Australia. You shouldn't believe that reptiles kill thousands of people every year. This statement is not true, it was invented by companies and other sources for whom it is beneficial to characterize these reptiles from the bad side in order to gain financial benefit.
Why does a crocodile have a long tail?
The most surprising part of Guiletta's research was that the alligators suffered these severe side effects from one-hundred-part-per-trillion doses of pesticides well below concentrations previously recognized as dangerous or even tested. He also found that the effects of exposure to one environmental estrogen could be compounded by exposure to another. These revelations "have changed the paradigm in how we deal with environmental disturbances," Ross says. Earlier research models looked at the environment in terms of additive effects or minimum acceptable doses of pollutants, and most environmental regulations are based on such models, but with hormone-disrupting compounds, any amount at all can be harmful.
Australia is a leader in crocodile conservation. In some territories of its states (in Western and Northern Australia, Queensland) there are about 100,000 - 200,000 representatives of this species. The saltwater (combed) crocodile is listed in the Red Book.
When were crocodiles found in Russia?
If we say that Russia is the birthplace of elephants, it will not be funny, but simply ridiculous. But that there were crocodiles in Russia is not such a fiction. As some reliable sources indicate, almost until the very end of the nineteenth century, these animals were found in western Russia, or, as they say, they were simply noticed.
Official science has come to the conclusion that, despite the desire to see these animals and love for them, crocodiles do not live in Russia. Great specialist on reptiles M.B. Efimov said that the last crocodile, whose place of residence was the Novgorod region, disappeared from Russian territory 15 million years ago. The harsh climate of the country could not suit them.
The life of crocodiles depends entirely on the environment in which they live. If the temperature outside is slightly below 20 degrees, they lie without moving. At temperatures of 30 degrees and above they also sleep. In order for the incubation period for crocodile eggs to pass normally, it will take 90-100 days from temperature conditions not lower than 25 degrees Celsius.
There is no place in Russia where crocodiles or alligators can live. Representatives of these reptiles will freeze and die while in the harsh Russian winters. True, there are times when one of the people brings a small animal from afar and keeps it at home. After it becomes large and dangerous, the would-be breeder sends it to a pond. In such an environment, a crocodile, doomed to inevitable death, becomes very aggressive and poses a danger to all creatures around it, including people.
Terrarium of the Moscow Zoo in Russia
Currently, you can see crocodiles in Russia only by visiting the “Terrarium” in zoos. In Moscow, it provides the opportunity to get acquainted with the following animals:
- The Mississippi alligator, which in its natural environment lives in bodies of water with fresh water, in the southeastern United States;
- A Chinese alligator that is protected by law internationally.
These alligators are the only animals that hibernate during the winter. Mississippi alligator, male Saturn, has interesting story own life. Before the outbreak of World War II, he was a resident of a zoo in Berlin and belonged to Hitler personally. After the end of the war, it came to England as a trophy, from where the country's government transferred it to Russia as a gift in 1946. So he began to live in the Moscow Zoo. The crocodile is approximately 85 - 100 years old, but this is not an exact figure.
About 225 million years ago, during the Mesozoic era, the planet was dominated by reptiles, which were then very numerous. Since those times, 21 species of crocodiles have survived to this day. Zoologists divide them into three families: alligators, true crocodiles and gharials. Alligators are found only in America, with the exception of one species living in China. Crocodiles live in Africa and South-East Asia, Australia and New Guinea, in some areas of America. Gharials live in India in the Ganges River. Gharial fossils found in South America, from which it follows that these crocodiles were widespread there in the Mesozoic.
Many species of crocodiles are included in the Red Book. The mad pursuit of crocodile skin, from which handbags and shoes, wallets, travel bars in crocodile skin cases, and briefcases are made, threatens crocodiles with their complete disappearance. The largest crocodiles are the saltwater, Nile and gharial. These are colossuses with a body 6-7 m long. There are giants up to 10 m long.
They are all predators with enormous strength. They feed on animal food from worms and beetles to antelopes and bulls. Only large crocodiles, reaching four to five meters, are dangerous to humans. Crocodiles attack people infrequently, but quite a large number of such cases have been recorded. The crocodile lies in wait for its prey in coastal thickets or hiding in shallow water near the banks of rivers and lakes, where wild animals come to drink.
The crocodile suddenly attacks the victim, grabs it with its teeth and drowns it instantly. It can first knock it down with a blow from its muscular and very strong tail. Crocodiles have cone-shaped teeth that are slightly curved back. Under each tooth there is another spare tooth, which grows fully when the old one breaks. The animal's tongue, attached to the lower oral cavity, is motionless. At the back of the mouth, the crocodile has a leathery valve that tightly closes the entrance to the respiratory tract and esophagus, so the crocodile is not able to open its mouth in water.
The crocodile's eyes have both upper and lower eyelids, located so that the crocodile, lying in the water, can survey its surroundings and look out for prey. The expression “crocodile tears” is known, but a crocodile does not shed tears. Simply, at a low ambient temperature, the nictitating membrane of the eye becomes inflamed, and the reptile “cries.”
A crocodile's teeth are not able to tear or chew large prey. In a large animal, it can tear off only small parts of the body, for example, ears or tail. Therefore, the dead animal is dragged underwater by the crocodile into its hole, where it waits for the skin on the corpse to soften in its mouth. The crocodile tears the already limp animal into many pieces and swallows it in huge pieces. After each swallowed piece, the crocodile sticks its head out of the water for several minutes, while it breathes heavily. So he pushes the meat deeper into the esophagus and then dives again.
The eggs are laid in a hole dug in the coastal strip of the reservoirs in which they live. The depth of the hole or hole reaches one meter. From 20 to 80 or more eggs are laid there. The eggs are similar in size to a goose egg. Having finished laying, the female fills the nest with soil and covers it with half-rotten leaves. She does not sit on the nest, but guards it for 2-3 months, staying nearby all the time and zealously protecting it from attacks by other animals and people.
Crocodiles hatch from eggs and make loud noises, similar to the croaking of frogs. This is a call for the nest to be excavated. The female immediately digs it up and begins to help the babies hatch. Some crocodiles hatch on their own, while others are helped by their mother. She carefully takes the egg into her mouth and uses her tongue to roll the egg across the roof of her mouth, releasing the little crocodile from the shell.
When all the babies hatch, she drags them all into the water. Some crocodiles, which are stronger, move towards the water themselves. The mother carries the newborns in her mouth. Crocodiles live on average 70-80 years, and sometimes 100 years or more. Interestingly, even at this age they are not toothless. They change teeth many times during their lives.