Meet the spider that builds a real live catapult

Professor Pip crouched low in a sunny rainforest clearing, his forest-green lab coat dusted with moss. From a bulging pocket he pulled out a bent green twig, a rubber band, and a small brown acorn.

"Gather round, gather round," he whispered. "Today we honor a tiny genius with eight legs."

Sofia and Theo tiptoed over, mouths already open with curiosity.

"Watch closely." Pip bent the springy twig into a wide arch, hooked the rubber band across it, and rested the acorn in the middle. He pulled the twig back — back — back — his tail quivering with the strain.

"Three... two... one—"

He let go. SPROING! WHOOSH! The acorn zoomed into the sky and plopped into a fern.

The children burst into giggles.

"That," said Professor Pip, adjusting his crooked spectacles, "is stored energy. When I bent the twig, I squished energy into it — like squeezing a spring. It wanted to snap back. As soon as I let go — whoosh — all that energy jumped into the acorn."

"Ooh," said Theo. "Like when I pull back a swing and let go?"

"Precisely, my clever friend! Now here is the astonishing part. In a rainforest not so different from this one, scientists just discovered a spider — a tiny one, smaller than your fingernail — that builds a catapult almost exactly like mine. But instead of a twig, she spins sixty long silk lines and pulls them all as tight as harp strings. It takes her four whole hours."

"Four hours?!" said Sofia. "That's longer than lunch!"

"Longer than lunch and nap time. Then — and this is the sneakiest bit — she paints the trap with a sweet perfume that green tree ants love. An ant marches up, takes a big brave bite... SPROING! The whole cone snaps loose, and the ant sails through the air right into her waiting web."

"So she never even has to chase it!" cried Theo.

"Exactly right! The ants she hunts are fierce — they'd bite her back if she went near their nest. So instead, her stored energy does the hard work for her. Scientists are calling her the ballista spider, after the giant catapults the ancient Romans used."

Pip looked up at the leaves swaying above. "A spider small enough to sit on your thumbnail, my friends — inventing a machine that took humans thousands of years to build."

He handed Sofia and Theo each a springy little twig. "Now — I wonder what you can launch?"