Fish scales: Primitive basis for modern metamaterials

Abstract Scales are a path breaking evolutionary adaptation that accompanied vertebrate evolution for the past 500 million years. Inherently lightweight with diverse shapes, sizes, materials, and distribution, they provide remarkable architecture-material enhancement, typical of metamaterials. Here we perspective on mechanical behavior fish scale inspired structures explain origins some their striking properties include directional nonlinearity, interlocking behavior, multiple penetration modes. We outline progress in understanding complexities these global local deformation modes conclude by offering future perspectives challenges.