Ogre-Faced Spider

Deinopis spinosa is the North American ogre-faced spider, one of about 60 species in the family Deinopidae. The species is famous for two extraordinary adaptations. First: the principal eyes (the rear-facing pair) are enormous relative to body size — they collect more light per unit area than any other spider's eyes, surpassing even cats and owls. Ogre-faced spiders can hunt visually in starlight. Behind each huge eye is a cellular layer that's destroyed and rebuilt fresh every dawn (the photoreceptive membrane is too sensitive to survive daylight). Second: the hunting method. The spider weaves a small rectangular silken net (1-2 cm) and holds it stretched between her two front leg-pairs while hanging upside-down from a horizontal silk thread. When prey passes underneath, she snaps her front legs forward, expanding the net 3-4× its resting size, and scoops the prey up. The cast takes about 20 milliseconds. In 2020, researchers at Cornell demonstrated that ogre-faced spiders also detect FLYING prey overhead by hearing — they pick up frequencies from 100 Hz to 10 kHz through receptors on their legs, then snap upward to catch the prey out of the air. They're the first spiders confirmed to hunt by sound.