undefined

setae

On each segment of an earthworm's body, except for the first and last one, are four pairs of tiny bristles called setae (Acadia) with aid movement. Although the worm's two musclar series, circular and longitudinal, allow the worm to stretch and pull itself, the setae give traction. As the worm stretches its body, it uses its bristly setae to anchor the anterior part of its body in the soil and then pulls and rest of its body forward. The traction gained by the setae is so good, predators such as robins may have a hard time trying to "pluck" the worm off the ground.