The pomelo is a large, sweet citrus fruit that grows on a tree. Although the fruit may fall more than 10 meters (30 ft), it survives undamaged! What makes this fruit so shock absorbent?

Consider: Researchers have found that the white inner layer of the pomelo’s skin forms a spongelike network of cells and space. The space between the cells increases as it gets deeper in the fruit and is filled with air or liquid. When the fruit falls and hits the ground, the liquid acts like a cushion. The pomelo’s skin compresses and stiffens, absorbing the energy instead of breaking.

Scientists are testing a shock-resistant metal foam that they designed based on the structure of the pomelo’s skin. They believe that similar structures could be used in designing helmets for motorcyclists, impact protection for vehicles, and protection against meteoroid impact on a space station.

What do you think? Did the pomelo’s shock-absorbent skin evolve? Or was it designed?