Sandworm (Dune) - Fremen and The Worms

Fremen and The Worms

Due to their size and territorial nature, sandworms can be extremely dangerous even to Fremen. The worms are attracted to — and maddened by — the presence of Holtzman force fields used as personal defense shields, and as a result these force fields are of little use on Arrakis. In Children of Dune it is noted that a weapon has been developed on Arrakis called a "pseudo-shield." This device will attract and enrage any nearby sandworm, which will destroy anything in its vicinity.

The Fremen manage to develop a unique relationship with the sandworms. They learn to avoid most worm attacks by mimicking the motions of desert animals and moving with the natural sounds of the desert, rather than the rhythmic vibration patterns that attract worms. However, they also develop a device known as a thumper with the express purpose of generating a rhythmic vibration to attract a sandworm (see worm charming). This can be used either as a diversion, or to summon a worm for the Fremen to ride.