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Arapaima vs. Piranha

Scales

In the dry season in the Amazon basin, big fleshy fish share extremely cramped watery quarters with hungry piranha – and their notorious guillotine-like bite. How does Brazil's massive Arapaima fish survive?

The secret to Arapaima's success lies in its intricately designed scales (above), which could provide “bioinspiration” for engineers looking to develop flexible ceramics.

Piranha

The inspiration to study the scales came from an expedition in the Amazon basin that materials science professor Marc Meyers took years ago. Meyers and colleagues found that Arapaima scales combine a heavily mineralized outer layer with an internal design that helps scales resist the piranha's razor-like bite. The mix of materials is similar to the hard enamel of a tooth deposited over softer dentin, said Meyers, who also teaches nanoengineering at the Jacobs School. “We have used our ingenuity to the maximum, but one way to overcome that is to look at nature,” he said.

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