Flashy iridescent shells might not seem like the best evolutionary strategy for bugs trying to avoid hungry birds. But in recent years, biologists have shown that iridescence—lustrous shifts in color, ...

The brilliant iridescent hues found in ammolite come from tiny air gaps in the fossils’ layers, a new study finds. By Alexa Robles-Gil Millions of years ago, squid-like creatures called ammonites swam ...