Discovered that the Amazon fish have scales that can resist Piranha's predatory teeth

The scales structure of a giant fish that can resist the sharp teeth of Piranha predatory fish is known as the 'sea monster' of the Amazon.

Divers inspect Pirarucu fish in the tropical area of ​​Europe's largest freshwater aquarium Aquatis.Photo: Reuters.

The fish in this study is Pirarucu (scientific name Arapaima gigas), one of the largest freshwater fishes in the world with a body length that can reach from 3 to 4.5m, weighs about 200 kg, lives in the river Amazon belongs to the territories of Brazil, Guyana and Peru.

According to the scientists, the scales of Pirarucu can be deformed but not scratched or torn when attacked by carnivorous fish Piranha, a small sized fish with sharp teeth. The bite force is said to be 3 times stronger than the American alligator.

Scientists from the University of California have discovered that the inner layer of Pirarucu fish scales is hard but very flexible, embedded by collagen with an outer mineralization layer.

The article also explained that other fish use collagen in the same way as Pirarucu, but the collagen layers in the giant fish's scales are thicker than any other species, equal to the thickness of a grain of rice.

The characteristic of Pirarucu fish scales has attracted the attention of engineers in the production of armor and armored composite, previously used to produce bulletproof vests with multiple layers of flexible fibers placed between plastic sheets. hard.

The article stated that the scales are the effective natural armor to protect themselves from predators without hindering their flexibility. Therefore, mimicking those structures in engineering can help create lighter and better materials for armor production.

Robert Ritchie, a material scientist who is also the lead author of the scientific research, added that while human-made armor must use a third material as a binder, the layers the scales are connected at the level of atoms and grow together to form a single solid mass but with flexible elasticity. In this case, the mineralized collagen is the structure that binds hard and soft materials together.

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