We humans are pretty resourceful creatures. We lack the abilities and body parts of many other animals like brute strength, agility, flight, claws and gnarly teeth. But our special ability is the power of our brain and the way that it can use resources to help us survive. We may soon be utilising a pretty cool new resource too…
While it’s pretty common knowledge that some spiders use their webs to catch prey and wrap them up for later consumption, spider silk also has many other uses. And believe it or not, not all spider silk is the same. In fact, a single spider can produce up to seven different types of spider silk for different purposes! There are edible silks, silks that help spiders to fly, bungee-cord silks, sperm-laden silks for surprise-inseminations, alarm-system silks, navigational silks and more! But the amazing characteristics of spider silk do not stop in their variety. As we will soon find out, spider silk may have some pretty cool uses for us as well.
If you’ve heard that spider silk is stronger than steel, then you heard correctly. Buuuut, it is (generally) not as strong as Kevlar. Spider silk is, however, tougher than both of them. Spider silk is the toughest biological material ever studied. In fact, silk that comes from Darwin’s bark spider is 10 TIMES STRONGER than Kevlar! Also, it is around 5 times less dense than steel, meaning that a strand of regular spider silk that made a circumference of the earth would weigh less than 500 grams. Some silks can be stretched to over 4 times their original length before they break, meaning that if you owned a pair of socks made out of it, you could turn them into stockings in an instant!
Many types of spiders also use extremely fine silk to catch the wind and carry them of to faraway magical lands full of knights, wizards and orcs. A good example of such a place is New Zealand. That’s right, there are a few populations of Golden Orb-Weaving spiders on New Zealand that are not permanent, and are only sustained because of a continued stream of their Australian immigrant cousins arriving by lofty web. How do they do this? Well, they let out a few, long but thin strands of silk that are still attached to their abdomen, and then wait for the wind to pick them up and carry them away…! Only a few get a lucky break though, most die a romantic death in the open ocean.
But back to human uses: we face a few hurdles before we start using the fine silk in our own products. First we have to try to make the silk dope (like a resin). This has been achieved with limited success by genetically modifying flies, E. Coli and goats (yes, goats) to produce it. Next time you go to a farm you might milk a goat to make a spider web… The problem is that while they have been able to produce some silk dope, they can’t produce much! The other thing we need to know how to do is ‘spin’ it as thin as spiders do. To date, we have only been able to ‘spin’ it between 4 and 25 times as thick as our 8-legged friends. (‘Spinning’ doesn’t really make sense here like it
does with cotton and wool, rather it is ‘pulled’, like making fibre optics). To give you an idea of how fine spider silk is (and why it is so difficult to make), the only piece of cloth made from spider silk that exists was made by 82 people who harvested the silk from over 1 million Golden Orb Spiders over 4 years.
So you should all look forward to the day when (with a little bit of scientific advancement) we can all have shoelaces that NEVER break. Huzzah!