Spiders straighten their legs with fluid pressure rather than with a pair of opposing muscles as we do, so after death the pressure goes and the legs curl up. What happens if you put the pressure back?
They open again. Researchers put a needle into the body cavity and pushed air through it, in place of body fluid, and all eight legs opened together. As the pressure dropped they closed around objects. The gripper, in the full sense of the word, lifted 1.3 times its own weight and worked hundreds of times before the joints began to wear.
work the other way round from ours. They have muscles that only flex, and the straightening is done by pushing body fluid into the joint.
So after death the pressure goes and the legs curl up on their own, which is the familiar posture of a dead spider. Hence the idea too: if pressure opened them in life, pressure can be supplied from outside.
The researchers put a needle into the body cavity and pushed air through. The body works as a single pressure chamber, so one injection point is enough to open all eight legs together. As the pressure dropped they closed around objects.
The gripper lifted 1.3 times its own weight and worked hundreds of times. The point is not revival but saving the manufacture of tiny joints that already exist. The sets the limit: a laboratory prototype of dead tissue dries and wears, and after some seven hundred cycles signs of deterioration had already appeared.
wat. The body of a dead spider, driven by air pressure, lifted an object 30 percent heavier than itself before wearing out after hundreds of cycles.
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An existing biological structure can sometimes replace the complicated manufacture of a tiny robotic part.
How do we know?
The researchers connected wolf spiders to a pressure system, measured grip force, and examined changes in the joints across a thousand cycles of opening and closing.
What is still unknown
This is a laboratory prototype made of dead material, and its decay is unavoidable: it dries and wears, and after some 700 cycles signs of deterioration had already appeared.
Learn something?
Where to next
A jumping spider sleeps and its legs curl. Is it dreaming?spiders
Where is a spider’s ear?spiders
What held two copper bowls together against a team of horses?air pressure