Sea lizard. Marine iguanas: photos, sizes, habits, interesting facts. What does the animal eat?

It seemed that these toothy and big-eyed marine predators went extinct tens of millions of years ago, but there are reports that ichthyosaurs are still found in the seas and oceans. Although these ancient creatures are similar to dolphins in many ways, it is difficult to confuse them with them, because the distinctive feature of ichthyosaurs is their huge eyes.

Dolphin-like lizards-eyed

Of the marine predatory dinosaurs, we are most familiar with plesiosaurs, and this is not surprising, because the famous Nessie is classified precisely as this type of aquatic lizard. However, in the depths of the sea at one time there were other types of predatory reptiles, for example, ichthyosaurs, which inhabited the seas and oceans 175-70 million years ago. Ichthyosaurs, which look like dolphins, according to scientists, were once among the first dinosaurs to return to the water element.

Unlike the plesiosaur with its long neck, the head of the ichthyosaur, like that of fish, was integral with the body; it is not for nothing that the name of this reptile is translated as “fish lizard”. For the most part, ichthyosaurs were not large in size, their length was 3-5 meters. However, among them there were also giants, for example, in the Jurassic period, some species reached a length of 16 meters, and in the polar regions of Canada, paleontologists discovered the remains of an ichthyosaur about 23 meters long (!), which lived in the Late Triassic.

These were toothy creatures, and their teeth were replaced several times during their lives. It is especially worth stopping at the eyes of ichthyosaurs. These reptiles had very large eyes, reaching 20 cm in diameter in some species. According to scientists, this eye size suggests that ichthyosaurs hunted at night. The eyes were protected by a bone ring.

The skin of these lizards had neither scales nor horny plates; according to scientists, it was covered with mucus, which provided better gliding in the water. Although ichthyosaurs are very similar to dolphins, they had a fish-type spine that curved in a horizontal plane, so their tail, like ordinary fish, was located in a vertical plane.

What did ichthyosaurs eat? It was widely believed that they favored the extinct cephalopod belemnites, but a team of researchers led by Ben Kier from the South Australian Museum refuted this idea. Scientists have carefully examined the stomach contents of a fossilized ichthyosaur that lived 110 million years ago. It turned out that there were fish, small turtles and even a small bird in it. This study allowed us to refute the hypothesis that ichthyosaurs became extinct due to the disappearance of belemnites.

It is curious that these marine reptiles were viviparous; this feature is clearly proven by paleontological finds. Scientists have repeatedly found the fossilized remains of ichthyosaurs, in the belly of which there were skeletons of unborn cubs. Newborn ichthyosaurs were forced to immediately begin an independent life. According to scientists, as soon as they were born, they already knew how to swim perfectly and get their own food.

Mysterious “weevil whales”

Ichthyosaurs reached their greatest diversity in the Jurassic period, and became extinct at the end of the Cretaceous. Or maybe they didn’t become extinct? After all, there is the opinion of a number of scientists that the same ichthyosaurs were warm-blooded and could well adapt to changing conditions in the ocean. When these lizards that have survived to this day die or die, their remains sink to the bottom, scientists accordingly do not find them and consider ichthyosaurs extinct.

In the early 1980s, the sailor of the Soviet cargo ship A. B. Fedorov, while sailing in the Indian Ocean, observed unusual marine animals, according to his description, very similar to ichthyosaurs. An eyewitness recalled: “I saw a light brown back and a characteristic whale fountain, but... it was not a whale or a dolphin. I saw such an animal for the first and so far only time in my life. The fact that this is some kind of mutant is excluded. There were at least five of these long-faced, toothy “whales” with large saucer-like eyes. More precisely, the eyes were in the center of the saucers.”

If this observation was the only one, it could be assumed that the sailor was mistaken and mistook quite ordinary inhabitants of the ocean for unusual creatures. However, in the spring of 1978, two members of the crew of the fishing vessel V.F. Varivoda and V.I. Titov observed a very strange sea animal with a toothy mouth. Titov described it this way: “The steep, rounded back of the head rose above the water by about 1.5 meters; a white stripe stood out brightly on the upper jaw, which, gradually expanding, stretched from the end of the muzzle to the corner of the mouth and was bordered below by a narrow black stripe... In the profile of the head was cone-shaped. The height of the upper jaw at the level of the corner of the mouth was about one meter... The total length of the head was from one and a half to two meters.”

V.I. Titov told the senior researcher at the Cetacean Laboratory, Candidate of Biological Sciences A. Kuzmin, about the mysterious animal he had encountered. The scientist had known Titov for 10 years by that time, so he took his story seriously. It is curious that Titov told him that he had seen similar “weevil whales” in the Indian Ocean more than once, and such animals usually kept in a small flock of 6-7 individuals, sometimes including calves among them.

Kuzmin showed his acquaintance many photographs and drawings of various sea animals, but Titov never identified his “weevil.” But when an image of an ichthyosaur accidentally caught his eye, he said that it was very similar to the creatures he had met.

A very living fossil?

So, there are observations of trustworthy people who have seen unknown large marine animals that are very similar to ichthyosaurs that went extinct tens of millions of years ago. Why not assume that ichthyosaurs, which at one time were distributed almost everywhere in all seas and oceans, managed to survive to our time only by significantly reducing their habitat?

It should be noted that even Soviet scientists took the messages of Fedorov and Titov quite seriously; information about a meeting with a large marine animal unknown to science was published in 1979 in the journal “Knowledge is Power.” The skepticism of scientists in recent times, of course, has been greatly influenced by the discovery of lobe-finned fish, which were considered extinct long ago. If she managed to survive to this day, then why couldn’t the ichthyosaur do it?

French scientists concluded that ichthyosaurs were warm-blooded. This conclusion was made based on data on the content of the stable oxygen isotope 18 0 in the fossil remains of ichthyosaurs. It was possible to prove that the body temperature of marine reptiles was higher than the body temperature of fish that lived with them at the same time. This discovery by scientists suggests that ichthyosaurs could well have survived, especially since they did not feed on belemnites alone. It remains to be seen that more compelling evidence for the existence of these prehistoric animals will emerge. Fortunately, many sailors now have both cameras and video cameras, and we can well hope to see footage of a whole flock of big-eyed and toothy creatures from the Jurassic period frolicking in the waves.

Prepared by Andrey SIDORENKO

In previous publications we have already touched on the topic of dinosaurs. Then we were talking about the ten largest species known to science. Today we want to introduce you to a list of the ten most ferocious sea dinosaurs. So.

Shastasaurus is a genus of dinosaurs that lived at the end of the Triassic period (more than 200 million years ago) in the territory of modern North America and, possibly, China. His remains were discovered in California, British Columbia and the Chinese province of Guizhou. This predator is the largest marine reptile ever found on the planet. It could grow up to 21 meters in length and weigh 20 tons.

In ninth place in the ranking is Dakosaurus, a saltwater crocodile that lived in the late Jurassic - early Cretaceous period (more than 100.5 million years ago). It was a rather large, carnivorous animal, adapted almost exclusively to hunting large prey. It could grow up to 6 meters in length.

Thalassomedon is a genus of dinosaur that lived in North America about 95 million years ago. Most likely, he was the main predator of his time. Thalassomedon grew up to 12.3 m in length. The size of its flippers reached about 1.5–2 meters. The length of the skull was 47 centimeters, the length of the teeth was 5 cm. It ate fish.

Nothosaurus (Nothosaurus) is a sea lizard that lived 240–210 million years ago in the territory of modern Russia, Israel, China and North Africa. It reached about 4 meters in length. It had webbed limbs, with five long fingers, which could be used both for movement on land and for swimming. Probably ate fish. The complete skeleton of Nothosaurus can be seen at the Natural History Museum in Berlin.

In sixth place on the list of the most ferocious marine dinosaurs is Tylosaurus, a large marine predatory lizard that inhabited the oceans at the end of the Cretaceous period (about 88–78 million years ago). It was the dominant marine predator of its time. Grew up to 14 m in length. It ate fish, large predatory sharks, small mosasaurs, plesiosaurs and waterfowl.

Thalattoarchon was a large marine reptile that lived more than 245 million years ago in what is now the western United States. The remains, consisting of part of the skull, spine, pelvic bones, and parts of the hind fins, were discovered in Nevada in 2010. Thalattoarchon is estimated to have been the apex predator of its time. It grew to be at least 8.6 m in length.

Tanystropheus is a genus of lizard-like reptiles that lived in the Middle Triassic about 230 million years ago. It grew up to 6 meters in length, and was distinguished by a very elongated and mobile neck, which reached 3.5 m. It led a predatory aquatic or semi-aquatic lifestyle, probably hunting near the shore for fish and cephalopods.

Liopleurodon is a genus of large carnivorous marine reptiles that lived at the turn of the Middle and Late Jurassic period (approximately 165 million to 155 million years ago). It is assumed that the largest known Liopleurodon was just over 10 m in length, but typical sizes for it range from 5 to 7 m (according to other sources 16-20 meters). Body weight is estimated at 1–1.7 tons. These apex predators likely hunted from ambush, attacking large cephalopods, ichthyosaurs, plesiosaurs, sharks, and other large animals they could catch.

Mosasaurus (Mosasaurus) is a genus of extinct reptiles that lived in the territory of modern Western Europe and North America during the Late Cretaceous - 70–65 million years ago. Their remains were first found in 1764 near the Meuse River. The total length of representatives of this genus ranged from 10 to 17.5 m. In appearance they resembled a mixture of fish (or whale) with a crocodile. They were in the water all the time, diving to a considerable depth. They ate fish, cephalopods, turtles and ammonites. According to some scientists, these predators are distant relatives of modern monitor lizards and iguanas.

Megalodon (Carcharocles megalodon) is an extinct species of prehistoric shark that lived throughout the oceans 28.1–3 million years ago. It is the largest known predatory fish in history. Megalodon is estimated to have reached 18 meters in length and weighed 60 tons. In body shape and behavior it was similar to a modern white shark. He hunted cetaceans and other large sea animals. It is interesting that some cryptozoologists claim that this animal could have survived to the present day, but apart from the huge teeth found (up to 15 cm in length), there is no other evidence that the shark still lives somewhere in the ocean.

Elasmosaurs are ancient lizards of the plesiosaur order. They reigned on the planet in the Triassic period, and in the Cretaceous period they were no longer there.

The average body length of Elasmosaurus was about 15 meters. The spine was formed from a large number of flat vertebrae, of which there could be up to 150 pieces.

The evolutionary process changed the limbs of elasmosaurs and turned them into large flippers.

These dinosaurs once lived in the sea, which was once located on the site of modern Kansas.

Elasmosaurs were the most unusual creatures of the suborder. They had a very long and flexible neck ending in a small head. At the same time, the elasmosaurus had a wide mouth, and its teeth were shaped like spikes.

In terms of the number of cervical vertebrae, these dinosaurs are certainly in first place among the rest. For example, you can compare the cervical region of a giraffe, which consists of only 7 vertebrae.

These lizards could catch the fastest fish; their long neck helped them grab agile victims.

At times, these dinosaurs went to shallow water, lay down on the bottom and swallowed small pebbles, which helped crush food and acted as ballast. About 250 stones were found in the stomach of one lizard. After studying the stones, scientists realized that elasmosaurs traveled several thousand kilometers throughout their lives and collected stones in different parts of the coast. Most likely, the offspring of elasmosaurs, like other ichthyosaurs, were born in the sea.

The remains of this creature were first found in 1868 by E. Kop. Bones of elasmosaurs have been found in the United States, Japan and Russia. These dinosaurs got their name due to the flat bones of the pelvic and shoulder girdle.

If you have been to the Galapagos Islands, then you have certainly encountered a marine iguana. The photo of this animal looks terrifying, but it is not without a special harsh beauty. Marine iguanas resemble dinosaurs that lived many millions of years ago. It is these animals that we want to pay special attention to in this article.

What does a marine iguana look like?

Lifestyle

Iguanas have keen eyesight and can swim and dive well. On land they have no enemies, so they allow themselves to be slow and lazy. But in the water you often have to escape from sharks, so slowness here can be disastrous. Therefore, the marine iguana adjusts its habits depending on the environment in which it is located.

Lizards' favorite pastime on land is basking in the sun. This is due to the peculiarities of the animal’s thermoregulation. The temperature of his body depends on the environment, and in order to receive enough energy for the normal process of life, it is necessary to accumulate heat and distribute it throughout the body. The marine iguana is not in danger of overheating. It releases excess heat through the skin of the belly.

Family relationships

Darwin called marine iguanas so scary the appearance of these lizards seemed to him. But in reality they are not too aggressive. To live, marine iguanas create family groups, which include one adult male and up to ten females. Juveniles stay separate, but also form groups. Sometimes several families unite into a large community.

Each male looks after his own territory. Outsiders are not allowed onto “family” lands. Seeing a stranger, the male warns about trespassing. He takes a stable position and begins to shake his head. If the intruder does not leave, a fight begins. Usually strangers enter occupied territory, having designs on the “master’s” harem, so serious battles take place.

Behavior in water

Marine iguanas rarely swim far from the shore. In water they make wave-like horizontal movements. Animals dive not for pleasure, but for food or to escape sharks. Male iguanas are bolder and stronger, they can swim longer than females. Young animals always stay in shallow water.

What else can a marine iguana surprise? Scientists have collected interesting facts related to the blood circulation of these animals. In order not to frequently rise to the surface and not to expend excess energy, the reptile saves oxygen while in water. Blood circulation slows down, only vital organs are supplied with blood. Thus, the lizard can survive under water for more than 1 hour.

What does the animal eat?

Of course, the marine iguana looks very impressive and creepy, but it is not a predator. Marine iguanas are classified as herbivorous reptiles. They eat mainly. It is for them that iguanas learned to dive. Some types of algae entwine coastal stones, and lizards carefully scrape them off.

Reproduction

Mating games are not the favorite pastime of the male iguana. He experiences attraction to his harem only once a year. During this period, the male’s scales become brighter, brown and reddish spots appear on it, which attract active females.

The fertilized female lays several eggs in the hole. Her clutch is small - 2-3 pieces. The female sprinkles warm sand on top of her treasure. Fights often occur around the laying sites, since there are few sandy areas on the Galapagos Islands; the islands are mainly composed of volcanic rock. Sometimes females destroy the clutches of their rivals, making room for their offspring.

In warm sand, the eggs mature for about four months. Then the young appear and join the parent group. The diet of young animals contains not only plant, but also animal food. Babies need this to grow.

Marine iguanas can hardly be called caring parents. They do not protect their offspring from predators. So most of the young become prey for seagulls, snakes or dogs and cats. People are trying to exterminate stray dogs in order to preserve the population of marine iguanas, but this does not help much. Unfortunately, these animals are today classified as vulnerable species.

A few words about adaptability to life

Constant contact with salt water while swimming or eating caused the sea lizard to develop special glands that relieve it of excess salt. These salt glands are connected to the lizard's nostrils.

Salt flies out when you sneeze. If nature had not taken care of creating these glands, the lifespan of lizards would have been significantly shorter, since their kidneys would not have been able to cope with excess salt. However, due to the fact that the species' habitat is limited only to the Galapagos, it is not very well studied. There is no exact information about the lifespan of these lizards.

Marine representatives have three orders of reptiles - turtles, lizards and snakes. Some sea snakes are not associated with land at all, even during breeding, since they are viviparous, never leave the sea and would be completely helpless on land. Sea turtles spend most of their lives in the open ocean, but return to the sandy tropical coasts to breed; Only females come to land to lay eggs, and males never set foot on land after hatching and moving to the sea.
Sea lizards are more associated with land. An example is the Galapagos marine iguana Amblyrhynchus crisiatus. She lives in the surf on the Galapagos Islands, climbs rocks and eats only algae. The fourth order of modern reptiles, crocodiles, apparently has no truly marine representatives. Living in salt water, Crocodylus porosus is associated mainly with estuaries; it feeds primarily on fish and probably cannot survive for long in a true marine environment.
^The kidneys of reptiles are not equipped to remove excess salt, and it is excreted by salt-secreting (or simply salt) glands located in the head. Salt glands produce a highly concentrated fluid that contains mainly sodium and chlorine in concentrations much higher than in seawater. These glands do not function continuously like a kidney; they secrete their secretions only occasionally in response to a salt load that increases plasma salt concentrations. Similar glands are present in seabirds, in which they have been studied in detail.
In the wet lizard, the salt glands pour out their secretion into the anterior part of the nasal cavity, which has a ridge that prevents the liquid from flowing back and being swallowed. Sometimes, with a sharp exhalation, liquid is ejected from the nostrils in the form of small splashes. The Galapagos iguana feeds only on algae, which are similar in salt content to seawater. Therefore, the animal needs a mechanism to excrete salts in high concentrations (Schmidt-Nielsen, Fanne 1958). s'
Sea turtles, both herbivorous and carnivorous, have large salt-secreting glands located in the orbits of both eyes. The gland duct opens in the posterior corner of the orbit, and the turtle, which has received a salt load, cries truly salty tears. (Human tears, which, as everyone knows, have a salty taste, are isosmotic with blood plasma. Therefore, the lacrimal glands in humans do not play a special role in the elimination of salt.)
^Sea snakes also secrete salty fluid when exposed to salt and have salt glands that open into the oral cavity, from where the secreted fluid is excreted (Dunson, 1968). Sea snakes are close relatives of cobras and are very poisonous, which has somewhat slowed down the physiological study of their salt metabolism, which has a number of interesting aspects.
Although marine reptiles have a mechanism for excreting salt in the form of a very concentrated liquid, the question remains whether many of them actually drink water in significant quantities?