Do You Even Lift, Bro? These Tangle-Web Spiders Snag Prey 50 Times Their Weight
AUDIE CORNISH, HOST:
Spiders weave their own futures, literally. Using silk of their own creation, they spin webs, meet mates, devise traps and ensnare their prey.
LAUREN ESPOSITO: If you can imagine it, spiders are probably doing it as far as silk goes.
CORNISH: Lauren Esposito is a curator of arachnology at the California Academy of Sciences. She says spider silk is awesome because it's the toughest biomaterial known to humankind.
ESPOSITO: The Caerostris spider, which is the Darwin's bark spider from Madagascar, their silk is 10 times tougher than Kevlar.
MARY LOUISE KELLY, HOST:
And with material that tough, spiders can do remarkable things. Gabriele Greco of the University of Trento in Italy has seen a spider capture and lift a lizard into the air.
GABRIELE GRECO: How can an animal, which is, like, 2 milligrams to lift something which is 100 grams? So there is something going on which is not just the muscles.
CORNISH: As for what exactly is going on, Greco studied this superpower in what's known as tangle-web spiders. And those spiders do have tiny muscles. He says what they're using here is a sort of silk pulley.
GRECO: The listener in this very moment can imagine me to attach to him an elastic band. And then, I pull it a little bit. So the listener in this very moment can feel the force that pushes towards me. And this is one band. But what if I start adding bands and bands?
KELLY: In this way, the spiders can snag their prey at ground level and then slowly hoist them into the air, adding band after band of silk, which creates the necessary tension to lift the animal closer and closer.
GRECO: This is basically the physics of the pulley, the mechanics of the pulley.
CORNISH: Greco and his colleague tested the spiders' weightlifting abilities by presenting them with a challenge of Olympic proportions. Could they hoist an animal much stronger and heavier than themselves, namely a cockroach?
KELLY: They filmed the spiders deadlifting, so to speak, their prey and found one spider was able to use its silk engineering to lift a cockroach 50 times - five zero - heavier than itself. The details were published this week by the Royal Society.
CORNISH: Lauren Esposito of the California Academy of Sciences wasn't involved in the work, but says it's another example of nature coming up with a unique solution to a problem.
ESPOSITO: I think what's really cool about this study is the amazing things that we begin to understand about nature when we start to combine fields. So this is a study that combines methods from physics with biological information.
KELLY: And as we untangle more of these engineering tricks from spiders, maybe we'll pick up a few ourselves.
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