Mud cracking by worms described in Nature, vol. 433, p475, 3 February 2005 and New Scientist, 5 Feb 2005. A team of marine scientists and an engineer from the University of Maine and Dalhousie University, Nova Scotia, have studied how a marine worm, Nereis virens is able to burrow through mud. The worm has a wedge-shaped head which it uses to make cracks in the mud by turning its mouth inside out and pushing into the mud. This opens a crack in front of the worm, which it moves into and then repeats the process. By using this crack propagation method the worm minimises the amount of energy needed to force its way through the mud. The cracks also open new surfaces for the worm to forage.
Editorial Comment: You could ask how evolving worms discovered they had the right shaped heads to crack mud before they developed the mouth-everting method of propagating the crack. There is no point in evolving a new structure unless the brain is simultaneously programmed for the animal to use it. Such a complex and vital link between body structure and behaviour is ignored by evolutionists. (Ref. design, worms, behaviour)