We know that sandworms are territorial and control an area up to 400 km2.

Paul leaned forward, touched Kynes’ shoulder. “How big an area does each worm stake out?”

Kynes frowned. The child kept asking adult questions.“That depends on the size of the worm.”

“What’s the variation?” the Duke asked.

“Big ones may control three or four hundred square kilometers. Small ones—” He broke off as the Duke kicked on the jet brakes.

From the Q&A What does the word "thumper" mean when used to measure distance?, we know that a worm can be ridden for approximately 500 km before being released.

At that point, the worm is tired, it's far from home, and possibly in the territory of another worm. In the Terminology of the Imperium, the entry for Shai-Hulud says (emphasis mine):

[...] Sandworms grow to enormous size (specimens longer than 400 metres have been seen in the deep desert) and live to great age unless slain by one of their fellows or drowned in water, which is poisonous to them.

So, is being summoned by the Fremen tantamount to a death sentence for a sandworm? Is there any evidence in any of the books that the worms return their home territory? Or that they carve out a new life, far from home, by ousting whatever worms happen to be where they are released?

1 Answer 1


It's not clear from the text of the original dune novels whether a sandworm will fight another for territory or simply travel until they find an area with no competing worms after being released by the Fremen.

Certainly the wormriders don't seem that worried about encountering another worm when crossing from one area to another so it may well be that the possibility of two healthy adult worms fighting each other (the same text describes them as "virtually indestructible") is basically nil.

On top of that, given that a released worm can easily return to its own territory (within a day or two) I think we can reasonably assume that the worm simply recuperates and then returns to its normal hunting grounds.

“We should leave this maker in deep sand,” Paul said.

“Yes,” Stilgar agreed. “We could walk to the cave from here.”

“We’ve ridden him far enough that he’ll bury himself and sulk for a day or so,” Paul said.

  • 2
    Point of order: I established in my other question that they can be ridden for about 500km. Their territory can be 400 square kilometers, which is a square 20km on a side, or a circle about 22.5km in diameter. So the worm can be way outside its territory when released.
    – Niall C.
    Apr 20, 2014 at 18:58
  • @NiallC. - You're right of course. Edited accordingly.
    – Valorum
    Apr 20, 2014 at 19:16

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