Turtles are undoubtedly one of the most successfully evolved species in the wild.
Turtles have a lifespan of hundreds of years, making them one of the longest living animals on the planet. As long as it has a complete body state, the turtle is a master of survival, possessing a strong defense that makes any opponent shy. All these feats are thanks to the unparalleled sturdy tortoise shell.
Hard shell makes turtle invincible?
Tortoise shells are the nightmare of countless predators – a party that can’t be escaped and can’t fly is right in front of you but can’t be enjoyed. Can’t chew, can’t swallow, no matter how hard the teeth are, it is difficult to penetrate this turtle shell.
You’ve probably heard the story of an eagle eating a tortoise: The eagle grabbed the turtle and flew up, then dropped it to break the turtle’s shell, then ate the meat inside. But in fact, most eagles only eat small turtles, they directly poke holes in the shells with their sharp beaks, then bite and eat the turtle meat.
Before an adult tortoise, the eagle does not usually attack directly. The fully developed tortoise shell is very hard and smooth, with a large surface area making it difficult for an eagle to grasp with its talons. The process of “butchering” a turtle is long and laborious, so the eagle would rather catch some hamsters and rabbits to eat.
In the wild, crocodiles are one of the few creatures that can directly destroy a “complete” turtle shell with a powerful bite. But at the same time, there are many real cases where crocodiles are powerless against hard shells.
Here we have to mention a common point: The bite force between different crocodile species is also different, and the body structure of turtles is also diverse.
In general, most turtles have a slightly curved domed shell – a structure that makes it difficult for predators to bite and crush. However, in order to facilitate aquatic activities, many species of water turtles will develop relatively flat and light shells, so their defenses are not as strong as tortoises.
Therefore, as ferocious as crocodiles, they rarely “seek things” with turtles with hard shells, but prefer river turtles as objects.
In addition, those who follow the animal world will have the comment: The jaguar is the only scary creature besides the crocodile that can bite through the shell of a turtle.
But in reality, jaguars only hunt sea turtles. When turtles come ashore to lay eggs at night, jaguars will take advantage of the opening to bite the turtle’s throat to death.
The reason jaguars can enjoy sea turtles as such normal meals is because sea turtles cannot fully retract their heads and limbs into their shells. Because they live in the sea all year round, sea turtles have a fish-like shape, which reduces friction and drag in the water, helping them swim faster and easier.
But at the same time, they also lose the ability to “shrink”. In the sea, the scales on their heads and limbs can essentially protect themselves, but on land it’s useless.
Therefore, it is impossible for the jaguar to “bite through the turtle’s shell” to kill the sea turtle. The jaguar can only attack when the sea turtle is in its most vulnerable breeding period and exposes the most openings.
In short, in the natural world, no animal can directly attack the turtle shell.
Experts’ nightmare
In Asia, there is a type of turtle that can be called the ultimate master of the “defensive withdrawal” strategy. They belong to the genus Cuora, also known as Asian box turtles.
From the photo above, you can also see, when this turtle enters defense mode, the limbs and head will completely retract into the shell forming an almost invincible “ball”.
This pattern of “total blockade” is very similar to the nine-belt tatu’s ability to curl up into a ball. The hard scales of the nine-belt tatu are even so powerful that there have been a few cases of bouncing bullets “killing” people.
Brazilian nine-belt tatu.
But from a biological point of view, tortoise shell and tatu armor are two different models.
The tatu’s armor is a patch of calcified bone formed by skin ossification, similar to the scale armor on the back of an alligator. Tortoise shell is composed of a dorsal armor and an abdominal layer. The carapace is again divided into 2 layers: the inner and outer layers, the inner layer is actually its skeleton – including the skeleton and ribs. The outer layer is composed of the stratum corneum or tough skin derived from the epidermis.
The two layers of the structure are staggered, increasing the solidity of the entire turtle shell. If tatu and alligator armor seems to be covered by a layer of chain armor, the turtle shell is an enhanced version of “chain and plate armor” with a multi-layered structure inside and out.
However, scientists focus more attention on studying the mechanical properties of the structure and biological applications of turtle shells.
Another mystery that researchers are very interested in is the evolution of tortoise shells.
In the long history of the earth, what species did turtles evolve from? What factors have pushed the complex structure of the tortoise shell to be gradually enhanced as it is today? This is a question that zoologists and archaeologists are eager to answer.
From giant turtles to small freshwater turtles, turtles have spawned countless “miracle” genera over the course of hundreds of millions of years.
Nowadays, scientists can only study with fossils.
But more than 100 years of archaeological discoveries have left scientists increasingly confused about this turtle. Because some major discoveries about ancient turtle fossils have completely “slapped” the conclusions of previous studies.
For example, in 1887, a 200-million-year-old paleontological fossil was discovered in Germany, this ancient creature called “Proganochelys” has fully developed a back carapace, so scientists guess it is ancestors of turtles.
And because its skull has a complete temporal region, tortoises are placed in the subclass Aura (a group of amniotes with skulls without a temporal cavity).
However, a fossil named Eunotosaurus was also unearthed in South Africa. This 260-million-year-old fossil shows its limbs, cones and ribs in the process of growing long and wide. This is a turtle in development.
However, this fossil has both upper and lower temporal sockets in its skull, so both Eunotosaurus and tortoise should be classified as diatoms (subclass Diopter). But according to current biological scientific knowledge, there is hardly an organism that can belong to the subclasses of No Ray and Two Rays at the same time.
Skull (top) and back of head (bottom).
In addition, there are conflicting findings about aquatic and terrestrial problems of turtles.
Currently, based on the turtle’s breathing pattern, movement pattern and abdominal shell structure, experts infer that turtles originated from aquatic animals, then came to land and developed. But according to the Triassic turtle fossils unearthed, scientists found that they were all located in the continental stratum.
There are many similar inexplicable archaeological discoveries and scientific research conclusions, these contradictory research findings have made the origin of turtles a common confusion and nightmare for scientists. research for more than 100 years. Therefore, experts are still working to excavate more fossils and conduct more advanced analysis and research to get a reasonable answer.
(Source: Thepaper)
Source: genk.vn
