Piranhas are known to be notorious killers of both humans and animals. However, this peculiar species of fish is well-protected by its skin which acts as a natural "bulletproof vest":
The fish, also known as pirarucu, gets up to 10 feet (3 meters) long and weighs up to 440 pounds (200 kg). Arapaima, a fish that can breathe air and survive up to a day outside of the water, inhabits rivers in Brazil, Guyana and Peru infested with piranhas, known for razor-sharp teeth, incredible bite strength and deadly feeding frenzies.
“It is true that the natural armour is similar to artificial body armour because of the similar scale overlapping system. However, the natural armour such as these fish scales is tough and much lighter, without impeding body flexibility and locomotion,” Yang added. “Remember that the fish scales were developed through hundreds of millions of years. They are very advanced.”
Scientists have been curious about the scales that this fish have, and upon conducting laboratory tests, they found a hard mineralized outer layer that is bound to a tough-but-flexible inner layer by collagen. This allows the fish to resist penetration when bitten by a piranha.
Image Credit: Reuters