Amazon Fish Has Super-Shield Against Piranhas

super-shield

An ‘armored’ fish living in the Amazon has evolved a remarkable multi-layer defense against the voracious piranha, materials scientists reported. Microscopic examination and mechanical testing have revealed the secrets of the arapaima, one of the biggest freshwater fish on the planet. Researchers led by Robert Ritchie at the University of California at Berkeley found its scales have an ultra-tough outer shell, designed to ‘promote tooth fracture at the point of penetration’. The scales also have a corrugated shape, designed to deflect pressure to a thicker, more elastic layer of collagen that lies underneath. The collagen itself is arranged in twisted overlapping layers, called lamellae, that are around 50 nanometres thick.” w/ photos

Bookmark and Share