Remnants of a spider web embedded in ancient amber suggest that some spiders' diets haven't changed much in millions of years. Separate research indicates that some groups of modern spiders that spin webs in the same pattern didn't stumble upon that design independently, as scientists had suspected, but evolved from a common ancestor. Both studies provide glimpses of spiders' evolutionary history.
Spider silk is made of proteins, so it degrades quickly and rarely fossilizes. When old specimens are found, they're most often preserved as single strands in amber, says David A. Grimaldi, an entomologist at