Along with the countless treasures amber has preserved for us for millions of years, it has also left us with spider fossils dating back to 380 million years. More interestingly is the fact that these over 300 million year old spiders also had the ability to produce silk which means that silk genes were present very early in the evolution of spiders.
Spider silk comes in a variety of shapes and forms. There are approximately 46,000 described species of spider each producing up to 8 types of silk. Some of these silks include dragline silk, a silk that supports the weight of the spider as a safetyline, flagelliform which is a sticky silk that traps prey, and aciniform silk, a silk used to wrap prey. The silk is secreted from a silk gland which contains concentrated viscous liquid protein. Each silk is therefore, comprised of a unique chain of identical proteins. The proteins that make up the spider silk are often referred to as spidroins.
Over the millions of years of evolution, spiders have engineered specialized ways to use these silks. A trapdoor spider is able to construct a camouflaged shelter out of silk while a red back is able to set a trap in the form of sticky snares comprised of nothing but silk. Some spider silks can be as powerful in strength as steel and kevlar and are able to absorb more energy than most things designed by humans. A silk cord with a diameter of a garden house can support the weight of a 737,000 pounds passenger jet. To make use of the strength of spider silk, scientist have engineered ways to genetically modify other animals including goats to allow them to produce silk. In the case of goats silk is produced with the milk from the mammary glands and then filtered out. The hope is to one day be able to mass produce synthesised spider silk.