Feeding my regal jumping spiders (Phidippus regius) some crickets off of tongs! Jumping spiders can jump many times their body length, to pounce on prey from a great distance. How is this possible? Spiders don’t have extensor muscles which means they cannot extend their legs completely with muscles the way we can. How do they extend their legs to jump? When a jumping spider has locked onto its target and is ready to jump/ambush, it uses a sudden change in hemolymph (blood) pressure to launch its