Conventional synthetic materials have fixed mechanical properties and suffer defects, damage, and degradation over time. This makes them unable to adapt to changing environments and leads to limited lifecycles. Recently, self-adaptive materials inspired by natural materials have emerged as a solution to address these problems. With the ability to change their mechanical properties based on changing mechanical environments, repairing defects, and maintaining their mechanical properties, these materials can lead to improved performance while decreasing waste. In this review, we explore self-adaptive phenomena found in nature that have inspired the development of synthetic self-adaptive materials, and the mechanisms that have been employed to create the next generation of materials. The potential applications of these materials, the challenges that existing approaches face, and future research opportunities are also discussed.