With the development of science and technology, human beings in front of animals, can be said to be like gods on high, in front of guns, any animal's rapid speed, strong bite force is not worth mentioning, then there are animals in this world that can resist bullets? Is there really one? That's the scaly-horned gastropod snail.
The hard shell of the snail is a shield to protect itself in the eyes of the snail, but in the eyes of humans, it is so fragile that it only needs to be squeezed and broken. But the scaly-horned gastropod snail, even if you use a Swiss Army knife, can only leave a shallow mark on his shell.
The scaly-horned gastropod snail (Chrysomallon squamiferum) is a mollusk that lives near hydrothermal vents at depths of 2400–2800 m on the deep seabed of the Indian Ocean.
We need to know that the seabed gradually forms hydrothermal vents along the crustal cracks, and the seawater seeps down along the fissures, is heated by the magma heat source, and then flows upwards in concentration, and erupts, thus forming a deep-sea hydrothermal vent. The first human discovery of hydrothermal vents was in 1979, when Alvin first discovered dozens of chimneys emitting black and white smoke on seafloor lava at a depth of about 2610-1650 m in the middle of the Eastern Pacific Ocean, as well as mounds formed by the accumulation of nearby copper, iron and zinc sulfides, and observed that mineral hydrothermal fluids of about 200-400 °C were ejected from chimneys with a diameter of about 15 cm at a rate of several meters per second.
Hydrothermal vent "black chimney"
At present, there are more than 150 known deep-sea hydrothermal vents, which are composed of water and some chemicals, and the ejection temperature is 60-350 ° C, and many such "chimneys" are formed.
The deep-sea environment has always been considered a forbidden area for life, because of the lack of food sources, but from the hot springs in the deep sea, that is, the seawater heated by the mantle column that gushes out of the hot springs, the mantle column carries a large number of sulfur, iron and other elements, and some chemical energy bacteria living near the hot springs can use these elements to generate energy for growth and reproduction, so in the overall cold, food-scarce, and extremely low biomass of the deep sea environment, the deep sea hydrothermal vents are like "oases of life", and they form an ecosystem based on the chemical energy fixed by bacteria and archaea.
View the hydrothermal vent field of the axial volcano from the Alvin submersible
These include some special creatures that are not found in other locations, such as the scaly-horned gastropod snail. (The theory that life now generally originated in black chimneys on the ocean floor suggests that the ancestors of early life may have been thermophilic microbes.) ）
Scientists have found that this snail has only been found to live in three deep-sea hydrothermal vents in the Indian Ocean, living in an area equivalent to two football fields, and the three earths are because in the Kairei district (located in the southwest Indian Ocean ridge) live black iron-rich, magnetic snails; in the Solidaire district (located in the central Indian Ocean ridge), the snails here are iron-deficient, white, and non-magnetic.
Scaly-horned gastropod snails collected from three origins preserve soft specimens, and the color varies according to the substances contained in the hot springs of the place of origin
This snail belongs to the marine gastropod mollusk species of the family Peltospiridae, which has no other relatives and is a monotypic species of the genus Scaly gastropod snail. This species is not only very different from other deep-sea gastropod species, but also from those belonging to the Neomphaloidea family, which is unique because of its life near chimneys.
<h1>The peculiarity of the scaly-horned gastropod snail</h1>
In 2001, scientists first discovered scaly-horned gastropod snails in the Kairei hydrothermal vent area of the Indian Ocean. Even in hydrothermal biomes, their presence is a very surprising discovery!
The scaly-horned gastropod snail is much larger than other species in the family Petospiridae. Most of the shells of the Peltospiridae family are less than 15 mm long, while the shell width of the scaly-horned gastropod snails is usually between 9.8 and 40.02 mm, the largest reaching 45.5 mm, and the average width of adults is 32 mm. Its head has two smooth, tapering antennae, but they do not have eyes and specialized connectors, in addition to the red gastropods they cannot fully retract the snail shell due to their large size, and they do not have the upper foot glands and upper foot tentacles like other snails and dragonflies, and in proportion, the heart volume of the squash gastropod snail is larger than that of many other animals, accounting for about 4% of the total body volume.
In the Pelospiridae family, the scaly-horned gastropod snail is the only known "simultaneous hermaphrodite" species, meaning that they have both male and female reproductive organs with high fertility, and the eggs laid are likely to rely on the yolk for nutrition. Scientists do not yet know the morphology of the larvae and fetal shell of the scaly-horned gastropod snail (currently the smallest immature individuals have 2. 2 mm shell length), but it is speculated that there may be a stage of planktonic diffusion.
An anatomical model of a 3D reconstructed scaly-horned gastropod snail Image source Alexandru Micu. paper
Of course, the most amazing thing is its hard shell, no gastropod has ever grown hundreds of scales like them, and no animal has ever been able to use iron like a scaly gastropod snail, because the iron compound of this snail is magnetic, some people even jokingly call them "Magneto on the seabed", two scaly gastropod snails together will be sucked, which is why they eventually evolved into "both hermaphrodites"!
The shell of the scaly-horned gastropod snail has 3 spirals, and the whole is compressed spherical. The shell has ribs and fine growth lines, and their shell can be divided into three layers: the outermost layer is a layer of "iron-plated" substance, it can be said that the body of the scaly gastropod snail is covered with iron compounds, about 30 microns thick, composed of sulfides of iron, mainly ferrous disulfide (the main component of pyrite) and triferrosulide (Fe3S4), the latter is magnetic, so the scaly gastropod snail will be sucked by magnets, true iron armor organisms!
The innermost side consists of calcified carbonate mineral chalcite, about 250 microns thick, while in the middle is a soft organic layer , equivalent to the outer membrane of other gastropods , about 150 microns thick. Iron provides power, while the organic layer absorbs the force of a predator, such as a crab wielding a claw, when attacking. In addition, the organic layer also has the function of heat dissipation.
In addition, at the junction between the scales, we could not find a pronounced shell hard protein growth line of the scaly-horned gastropod snail. No second of either living or extinct gastropod species has scales that grow like this on the skin; no other known living animal can make such use of iron sulfides, whether skeletal or exoskeletons, in any other known living animal.
<h1>Causes and research on the formation of scaly-horned gastropod snails</h1>
Because the scaly-horned gastropod snail mainly lives in the hydrothermal orifice area on the indian ocean floor, and the hydrothermal vent area is rich in minerals such as iron sulfide and ferrous sulfide, the reason why they can form such a hard shell is actually due to the symbiotic symbiotic bacteria in the scaly gastropod snail.
Snails of the black variant have some bacteria that the white variant does not have. Scaly-horned gastropod snails live on the surface and inside of the body of beneficial bacteria that can help them produce iron sulfides. Sulfides from the hydrothermal vents on the seafloor are highly toxic, but the toxicity disappears when these sulfides combine with minerals to form a solid, so bacteria may play an important role in the weakening of the toxicity of these compounds. That is to say, the scaly gastropod snail is not only plated with a layer of iron armor, but this layer of iron armor will continue to accumulate on the shell of the scaly gastropod snail, which will cause their shell to become thicker and harder over the years. Scientists speculate that this layer of iron armor is still poisonous.
However, because of the scarcity of samples, some scientists also believe that the scaly-horned gastropod snails can form such a hard shell to their own credit
The hard shell of the scaly gastropod snail is comparable to an alloy, and even a bullet cannot penetrate, of course, we also want to point out that the hard shell referred to here refers to the black snail with rich iron content and magnetism living in the Kairei district; the snails here in the Solidaire district have no magnetism, so they do not have an "iron armor" to strengthen protection.
This snail is completely resistant to the close-range fire of small-caliber pistols and is unharmed, and the US military has experimented with rifle bullets and has not caused much damage to its shell. At present, the US military is studying these snails, hoping to give some inspiration to the design of soldiers' armor. It is said that the U.S. Military conveniently modeled a similar material to make infantry armored vehicles based on the shell of a scaly-horned gastropod snail.
Of course, this snail also has very important engineering value, in the paper "Protection mechanisms of the iron-plated armor of a deep-sea hydrothermal vent gastropod", the authors point out:
The design of synthetic bio-excitation materials and structures that mimic natural systems is a huge field with great potential to transform many fields of engineering and science, including civil engineering, biological engineering, mechanical engineering, materials science and engineering, chemical engineering, and aerospace. There is a lot of design space for synthetic multilayer structural composites for protective applications.
The multi-material, three-layer design and favorable bending geometry of the scaly-horned gastropod snail allows for structural strengthening, reduced radial displacement, penetration resistance and stability over thermal shock, even when there is a large mismatch between the constituent materials. It will improve the performance of human, vehicle and structural armor. In addition, the geometry of layers and the influence of material selection between different layers have been an important research topic for optimizing engineering materials with sharp and gradient layers to improve thermo-mechanical properties. Combining material layering, composition gradation, microlayer and macroscopic geometric design in the shells of gastropod mollusks can also provide important references for optimizing multi-functionality in engineering design to improve their mechanical properties and protective properties.
It can be said that the shell of this snail has important research value, but the scaly-horned gastropod snail is difficult to survive in artificial environments, and even so, they have survived in the aquarium under atmospheric pressure for more than 3 weeks.
In addition, the three deep-sea hydrothermal vents that have only been found to live in the Indian Ocean, covering the equivalent of two football fields, are currently only found to be living in two soccer fields, and two of the three hydrothermal vents are facing deep-sea mining activities. Large-scale mining of the high seas requires permission from the United Nations' International Seabed Authority, and it is reported that large-scale mining of the area is expected to begin in 2020
The International Union for Conservation of Nature (IUCN) also recently announced that the Scaly-horned Gastropod Snail (Chrysomallon squamiferum) is on the endangered species list, which is also the first animal endangered due to deep-sea mining.
Large-scale mining activities will also lead to the complete extinction of this snail, it seems that even the hardest iron shell can not resist the damage of human beings to the environment.
Source:
1. The paper "The Most Amazing Deep-Sea Snail" Wang Recall
2、Yao, Haimin; Dao, Ming; Imholt, Timothy; Huang, Jamie; Wheeler, Kevin; Bonilla, Alejandro; Suresh, Subra; Ortiz, Christine (2010).《Protection mechanisms of the iron-plated armor of a deep-sea hydrothermal vent gastropod》