The alligator turtle (Macrochelys temminckii) is an aquatic reptile that belongs to the Chelydridae family. Its most distinctive characteristic is its carapace, in which three dorsal ridges are evident, formed by large scales with spikes..
This structure is brown, black or greenish in color, due to the growth of algae on it. Around the eyes, it has a bright yellow hue, which, by forming certain patterns, contributes to the camouflage of the animal with the surrounding environment.
A relevant morphological adaptation is found in the language of the Macrochelys temminckii. This is black and ends in a red appendage, shaped like a worm. When the reptile wants to hunt, it stays motionless at the bottom of the lake and opens its mouth. Then it begins to move its tongue, which attracts the fish. The capture of the prey is immediate, when closing the jaws.
This reptile is the largest freshwater turtle in the United States, where it is endemic. It usually inhabits slow bodies of water, such as rivers, streams, ponds, and lakes. Due mainly to its poaching, the alligator turtle is listed by the IUCN as vulnerable to extinction from its natural habitat.
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The tongue of the alligator turtle is black, but at the tip it has a red vermiform appendage. This is mobile and, due to its resemblance to a worm, serves as bait to attract prey, when the turtle keeps its mouth open to hunt the animals.
In this species, sexual dimorphism is evident. Thus, in the female, the cloaca is located just at the edge of the carapace, while in the male it extends outside this.
In relation to the base of the tail, in the male it is much wider, because in that area the reproductive organs of this are hidden..
Macrochelys temminckii It is the largest freshwater turtle in the United States, with a record shell length of 80 centimeters and an approximate weight of 113.9 kilograms.
In general, the average length of the carapace is 50 centimeters, although there are species that can measure between 60 and 80 centimeters. Regarding its weight, it is usually between 50 and 75 kilograms.
This aquatic reptile reaches reproductive maturity when it weighs around 8 kilograms and its length is 33 centimeters. However, they continue to grow throughout life..
One of the main characteristics of this species is its thick and long carapace. This is a plate of bone tissue that is not associated with the skeletal system of the animal.
In its constitution there are numerous pleural and vertebral shields, with spikes and arranged in rows. Thus, three dorsal ridges are formed, with complete or incomplete keels. These extend from the front to the rear of the protective shell..
Additionally, near the edge of the shell, it has a row of scales, between the outer margins and the inner costal. As for the caudal notch, located on the posterior edge, on the tail, it is usually narrow and triangular.
The plastron is cross-shaped and small, considering the dimensions of the shell. The alligator turtle cannot retract its legs or head into the shell, so it uses other mechanisms to ignore threats.
The Macrochelys temminckii it has a coloration that could vary between gray, black, brown or olive green. Its shell is often covered in algae, so it can sport various shades of green.
Around the eyes it has bright yellow patterns, which help to keep the turtle camouflaged with the environment where it lives..
The alligator turtle has a large, heavy head, which, viewed from above, is triangular in shape. The size of its head contributes to the generation of a greater force in chewing. This is due to the fact that it has a large muscle mass compared to other turtles of similar size..
Their eyes are located laterally and are surrounded by fleshy star-like filaments. As for the mouth, it is made up of a lower jaw and an upper jaw..
Both bone structures are covered by a horny layer of keratin and ends in a point. This reptile lacks teeth, but uses its sharp beak to rip or cut its prey.
The throat, chin, and neck areas are lined with long, pointed tubercles.
Many animals use the bite with their jaws as a powerful defense weapon. The alligator turtle is one of these, since it will try to bite anything that represents a threat.
This species cannot withdraw its head or its limbs inside the shell, so they use this defense mechanism. When in water, the adult animal has very few predators.
However, on land it can be threatened by raven, raccoon and man. If he Macrochelys temminckii is attacked or captured, violently moves its head forward and uses its imposing jaw to bite.
Thus, while extending its neck, it also closes its mouth, clinging to the attacker and inflicting a painful wound..
In Belgium, at the University of Antwerp, a study was carried out on the bite pressure of 28 species of turtles. The results revealed that the common toad-headed turtle (Phrynops nasutus) had the hardest bite, at 432 newtons. This was more than double the score of the alligator turtle, which had 158 newtons..
Newtons are not units of force that are used every day, so to understand a little better the force of the bite of the Macrochelys temminckii, some comparisons can be made.
Thus, the human being can generate bites between 200 and 600 newtons, while a shark has one of more than 18,000 newtons. In this way, although the alligator turtle has a strong bite, it is not one of the strongest, not even within the Testudine order..
However, the handling of this species must be done with care, since, if it feels threatened, it will defend itself by biting. With this action it could break the handle of a broom and in a few cases bites have been reported on the fingers of humans.
-Animal Kingdom.
-Subkingdom: Bilateria.
-Phylum: Chordate.
-Subfilum: Vertebrate.
-Superclass: Tetrapoda.
-Class: Reptilia.
-Order: Testudines.
-Suborder: Cryptodira.
-Family: Chelydridae.
-Genus: Macrochelys.
-Species: Macrochelys temminckii.
The alligator turtle is endemic to the North American continent and is found mainly in the southeastern United States. Thus, it occupies the regions of eastern Texas, northern Florida, western Illinois, southeastern Iowa, southern Georgia and in South Dakota.
Additionally, it can be found southeast of Kansas, east of Oklahoma, south of Indiana, west of Tennessee, and west of Kentucky. It also lives north of the Gavins Point Dam, which borders the states of Nebraska and South Dakota..
One of their favorite habitats is the drains from the Gulf coasts in Alabama, Arkansas, Mississippi, Louisiana, Georgia and north of Florida, down to the Suwanee and Santa Fe rivers. It should be noted that there are some non-native populations, established in South Africa.
The Macrochelys temminckii inhabits spaces of fresh water and slow movement. Thus, it is found in the depths of canals, swamps, lakes, rivers and in lakes. This species lives in temperate regions, locating in marshy fields, brackish wetlands, reservoirs and ponds..
While the young are raised on the surface and near small streams, the adults are found in the river systems that drain into the Gulf of Mexico, among others..
The movements towards the earth are made almost exclusively by the females, since they nest on the ground. Also, the juveniles tend to move frequently between the nest and the water..
The average distance in which the nest is located is 12.2 meters from the nearest water, although they have been found up to 72 meters from the body of water.
In relation to the range of households, its size varies between 18 and 247 ha. Within these, the caiman tortoise moves about one kilometer a day, with a daily average of 27.8 and 115.5 meters / day.
Throughout the year, the M. temminckii You can select different habitats because, among other factors, energy requirements may vary. In this sense, changes in water temperature can cause thermoregulatory behaviors.
The alligator tortoise regulates its body temperature by moving to other microhabitats, where the thermal characteristics are more favorable..
Likewise, the pregnant female can select shallower areas than the males, just before leaving the water to nest. In turn, the female prefers warmer waters, to guarantee the full development of the egg..
The populations of the Macrochelys temminckii have suffered a massive decline, mainly due to human interference.
In this sense, currently said aquatic reptile is in danger of extinction in several states in the US, including Indiana, Kentucky, Kansas, Missouri and Illinois, where it is protected by state laws..
This situation has caused the IUCN to categorize the alligator turtle as a species that is vulnerable to extinction..
Poachers capture the species for its shell and for its meat. It is also usually taken from its natural habitat to be sold illegally as pets in markets..
In addition to this, there are local threats such as incidental trawl fishing or nest predation..
Another aspect that afflicts the caiman turtle is the destruction of its ecosystem. Much of the water where it lives has been drained and turned into farmland. This causes the reptile to move to other areas, altering its natural distribution..
In addition, man pollutes the water, thus altering the basic acid levels of the water and its chemical composition. In this way, the reproductive cycle is affected, among other aspects, resulting in a decrease in the population and the possible degeneration of the gene pool..
In addition to all this, the fact that the caiman turtle matures at a late age and has a low reproduction rate, populations take a long time to recover from the decline in the number of species that comprise it..
In several regions of the United States, this reptile has been classified as threatened, so its hunting is prohibited. Its capture is prohibited in Florida, Arkansas, Georgia, Missouri, Indiana and Tennessee.
If they can be hunted, with the application of a permit, in Alabama, Kansas, Illinois, Louisiana, Texas and Oklahoma. Likewise, it is included in Appendix III of CITES, so its international trade is controlled in this way..
In addition, this international organization constantly evaluates the situation of Macrochelys temminckii, in order to determine if additional measures or the enactment of other laws that complement the protection of the species are necessary.
Among the actions carried out by various organizations, such as the Florida Fish and Wildlife Conservation Commission, are the implementation of methods to improve the quality of the waters and the conservation of private lands that border the habitat.
In this same vein, in Illinois, alligator turtles have recently been reintroduced in various constructed watersheds. The purpose of this action is to preserve the native gene pool.
Maturity in the Macrochelys temminckii It is reached when both the male and the female are between 11 and 13 years old. Mating occurs annually, those that inhabit the southern part of the continent, such as Florida, unite at the beginning of spring.
Those alligator turtles that live north, in the Mississippi Valley, breed at the end of the spring season. On the other hand, during the mating season, the males become territorial.
In copulation, the male climbs on top of the female and grasps her shell with his powerful legs and strong claws. Then he inserts his penis into the cloaca and ejaculates the sperm. This species is polygynous, so males and females can unite with more than one pair..
Fertilization is oviparous, where the female can lay from 8 to 52 eggs. Before nesting, it comes out of the water and crawls between 45 and 50 meters. Then it digs a hole with its hind legs, where it lays the eggs. Later he covers them with sand, moves away and returns to the river.
The reason for building the nest away from the reach of the water is to prevent it from flooding the space and can drown the young. In terms of incubation, it lasts between 11 and 140 days.
Parents are not involved in raising young people. The male, after mating, invests neither time nor energy in the young. For its part, the female, after nesting, does not care for her young..
The birth occurs in autumn and the young do not have parental protection, so they often become easy prey for their predators. Young feed on tadpoles, snails, crayfish, and other small invertebrates.
The sex of the offspring will depend on the temperature at which the eggs are incubated. When the temperature in the sand reaches 29 or 30 ° C, the vast majority of newborns are female. In contrast, males are born when the incubation temperature is between 25 and 27 ° C.
In investigations carried out on the incidence of temperature in the embryos of the alligator turtle, the results indicate that incubation in extreme temperatures, both high and low, negatively affect embryo survival.
In the event that it survives, the young tend to be smaller. Likewise, the growth of the newborn is faster when the water temperature is warmer, approximately 30 ° C.
The alligator turtle is omnivorous and its food preference is fish and invertebrates. They also tend to eat carrion, which comes from food scraps or dead animals. Their diet consists of fish, crayfish, worms, aquatic birds, such as ducks, snakes, mussels, snails, and amphibians..
Occasionally it might feed on otters (Myocastor coypus), aquatic rodents, muskrats (Ondatra zibethicus), squirrels, possums (Didelphis virginianus), armadillos (Dasypus novemcinctus) and raccoons (Procyon lotor). These are captured when they try to swim or approach the water's edge.
Another regular source of nutrients are plants, of which it consumes its stem, seeds, bark, roots, leaves and fruits. These include walnuts, oak acorns, wild grapes, tupelo and palm heart fruits..
According to studies conducted in Louisiana, a high percentage of the food found in the stomach of the alligator turtle is made up of other turtles. However, in general, the fundamental prey of this species is fish.
Some of the fish that make up their diet are the Cyprinus sp., Lepisosteus sp., Y the Ictalurus sp. The consumption of the prey can vary according to the availability of these in the habitat and the region where the turtle lives..
However, after the fish, the other most consumed prey is the crayfish (Procambarus sp.), followed by mollusks. Then there are the otter, armadillos, muskrat, raccoon and other small mammals. Finally there are the snakes and the waders.
The consumption of plant material may be due to it being taken intentionally or accidentally, while capturing prey.
The Macrochelys temminckii It is an active hunter at night, since at that time of day the external temperature is the most suitable for this activity. However, during the day, this reptile remains motionless and silent at the bottom of the water, camouflaged with the fallen leaves and branches..
In that position, it opens its mouth and keeps it that way, waiting for its prey. Meanwhile, the alligator turtle moves its tongue, imitating the movements of a worm. This attracts fish and various invertebrates..
When prey is close, it quickly closes its jaw. If the animal is small, you can swallow it whole, but if it is large, cut it in two before eating.
At times, this species tends to bury itself in the mud, leaving only the nostrils and eyes out. In this way, it goes unnoticed and can surprise prey..
The alligator turtle is a solitary animal, which exhibits little or no behavior associated with parental care. There is also no evidence of the existence of any type of social structure or interactions between these.
The average home range is 777.8 meters. The females have a greater range than the males and the young ones one greater than the adults. Also, the Macrochelys temminckii you can stay in the same place for an average of 12 days.
Most of the time it is submerged in water, where it could be kept for no more than 40 or 50 minutes. Then it comes to the surface in search of oxygen. In water, prefers areas with submerged cover, such as overhanging shrubs and logs.
The alligator torture can vary its location, depending on the season. Because of this, the Macrochelys temminckii shows a migratory behavior, where some populations make movements at certain times of the year. The intention is to locate hibernation sites and breeding areas.
This species uses chemosensory signals to locate its prey. In addition, it uses gular pumping, through which, through the throat, it extracts a portion of the water that surrounds it.
In this way, you can test it and identify some chemical elements that are released by certain animals. In this way, adult turtles can locate musk and mud turtles, which are buried in the bottom mud..
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