Dune Wiki
Dune Wiki
Enc2 This article or section refers to elements from the Dune Encyclopedia.
There are separate pages for this subject as it appears in the other canons, the reasons for this are explained here

Sandworm emerged above desert dunes (The Dune Encyclopedia, art by Matt Howarth)

Adult worm - Illustration for the Dune Encyclopedia by Matt Howarth

Screenshot 2019-02-27-18-46-44-2

Adult worm - Illustration for the Dune Encyclopedia by Matt Howarth

Screenshot 2019-02-27-18-46-57-1

Sandworm Lifecycle - Illustration for the Dune Encyclopedia by Matt Howarth

File:Screenshot 2019-02-27-18-46-44-1.png

Sandworm larval stage- Illustration for the Dune Encyclopedia by Matt Howarth

The Sandworms (Fremen: Shai-Hulud; taxonomic name: Geonemolodium arraknis, also Shaihuludata gigantica) were the dominant life form on Arrakis before the time of Leto II.

The Adult Worm[]

One of the difficulties of studying the organism was the immense size of the adult. Larger male specimens leached lengths exceeding 400 meters and were close to 100 meters at the widest point. The smaller female measured approximately 100 by 20 meters. The mouth of the male worms has been measured at 80 meters in diameter. A set of 1,000 or more organic carbo-silica crystal teeth surrounded the mouth in a circular pattern. As described below, the teeth were used for defense of territory, rather than for ingestion of nutrients.

The adult worm was made up of 100 to 400 segments. Each segment possessed its own primitive nervous system. Respiration was accomplished through pores in the tough, silvery-gray outer skin. There was no circulatory system. As such, since most of the nutrients were in the form of gases. Each segment had a series of membrane "baffles" to absorb nutrients.

The "gut" was a hollow tube running the full length of the worm, servicing all of the segments. It did not function for the elimination of waste products nor for ingestion or digestion of food. Each worm had one segment, near the anterior portion, which was a specialized reproductive segment. It is not known what stimulated the differentiation of this reproductive segment.

The Larval Form[]

Sandtrout (or "Little Makers" as the Fremen called them) were the larval form of the sandworm. They were large, unicellular organisms with a flexible peptidoglycan cell wall. Nutrients were absorbed from water and air through the cell wall. Individual sandtrout  were rarely over 20 cm long and 6 cm wide. Their shape tended to be pleiomorphic, adapting to the environment. It was not uncommon to find many sandtrout attached to one another, walling off several liters of water from the surrounding environment.


A female worm reached sexual maturity after approximately 1,000 years of maturation, the male worm readied maturity after approximately 1,100 years. Mating began when a gravid female developed an egg sac in her reproductive segment. At that time, she chose a nest site and built a nest by raising herself to half-length height and throwing herself down to "blast" out a nest. This rhythmical thumping and grinding noise called a male worm. The Fremen made use of this fact — one could hardly term it a "mating habit" — to call a worm with "thumpers," devices which imitated the nest-building sounds of a female worm.

The male moved rapidly to the nest site and devoured the female. Compounds in the outer skin of the female caused the male to become dormant for a period of several weeks during which he remained buried in the nest site. The highly resistant spice-fiber egg case in the female reproductive segment was retained in the male reproductive segment, where fertilization occurred by an unknown process. After fertilization and possibly a period of development and cell division, the male deposited the spice-fiber egg case into the sand nest, presumably by egestion, and left the nest with the egg case buried deeply below the surface of the sand. At this stage of development (schizontal) the zygotes underwent an asexual cell division producing a spongiform merozygospore containing thousands of future larvae. The merozygospore ruptured, releasing the sandtrout. The sandtrout were efficient water scavengers. They traveled hundreds of kilometers through the sand seeking out water, joining their bodies with one another to transport the water back to the nest site. Many of the nutrients required by the sandtrout were breakdown products contributed by the female body. The sandtrout produced exoenzymes which digested the nutrients to fragments absorbable by the larvae. As the sandtrout brought water to the nest site, it mixed with the excretions of the larvae to form the pre-spice mass. The chemistry of the reactions has not been determined; however, it is known that CO2 was evolved and built tremendous pressures within the mass. When the pressure built sufficiently, there was a powerful explosion, often termed a spice-blow. All of the products of the pre-spice mass were brought to the surface of the sand, where the action of sun and air rapidly changed the pre-spice to melange. Again the bio-chemical process is unknown. During the "blow," many sandtrout in the immediate vicinity were killed. Most scholars agree that the cell walls of these dead larvae were the source of the amino-sugars in melange.

The chemical reactions during the spice blow triggered changes in the surviving larvae, stimulating them to join their bodies in a premetamorphic stage. At this point, changes in metabolism began, so that the combined larvae became similar to the adult worm. Water gradually became toxic, and rudimentary autotrophy developed.

The pre-metamorphic stage consisted of joined sandworms, each capable of metamorphosing into an individual sandworm segment. The metamorphic process took over 1,050 years. One segment differentiated to become the head segment with teeth, and another differentiated into the reproductive segment. Posterior segments were relatively undifferentiated and could reverse the metamorphic process to become sandtrout if environmental conditions were unfavorable to the adult worm. Most commonly this latter occurred in the presence of water. The juvenile form of the worm was neither male nor female. This small (20 to 30 meters long) form of the worm was captured by the Fremen for drowning to produce the spice essence for their spice orgy. Most of these juvenile worms became females. The stimulus for development of a male is not known. One theory holds that subtle changes in the environment due to the absence of an adult male triggered the formation of a male, but this is not proven. Each male worm had a territory of 300-400 square kilometers which he defended against intrusion by another male. Fights between two males rarely ended in death. The protagonists used their teeth to hook the ring segments of the opponent, opening the segment to the entrance of sand, causing irritation. One worm eventually became sufficiently uncomfortable to break off the battle and retreat. Although the fight was not directly fatal, occasionally sand caused sufficient irritation to allow entrance of an as yet undetermined virus, eventually resulting in the death of the worm.


The adult G. arraknis was a true autotroph, producing all of its nutritional needs from inorganic compounds on the planet surface. The energy to drive the synthetic reactions was obtained by the travel of the worm through the sand which caused an electrostatic charge differential. The resulting electrons passed to an electron acceptor believed to be a cupri-cyanide compound, the reduced form of which accumulated in the worm body. The electron donor was probably SiO2, although the precise mechanism is unknown. Molecular oxygen was evolved during the reaction. The presence of water caused the electrons to be discharged abnormally because the anions and cations on the worm body dissolved in the water. Thus, water was a poison to the worm.

The heat from the friction of the travel of the worm through sand drove the synthetic reactions to completion. Most of the nutrients produced were gaseous: methane, ethane, propane, and butane, but some were liquids, such as formic acid, acetic acid, propionic acid, and butyric acid. Excess gases not utilized for nutrients were literally ignited by the heat of sand travel. Thus, the worm always had a flame deep within the body cavity. The excess heat also aided in driving the synthetic reactions, keeping the nutrients in gaseous form for absorption, and vaporizing any stray H2O.

Knowledge of the metabolism of the sandworm is necessarily incomplete, not only because of the size of the creature, but also because of the presence of many acidic compounds in the worm's body. Besides the organic acids, concentrated hydrochloric and sulfuric acids have also been detected. In some way, the living worm buffered itself against these acids, but, once the worm died, the body was rapidly digested by them. The most resistant structures were the teeth, which were gathered by the Fremen to become the legendary crysknives.

One of the mysteries of the metabolism of the sandworm is the source of hydrogen in the organic compounds. Obviously it could not come from water. One theory is that molecular hydrogen was fixed, although the reactions have not been discovered.

Some research undertaken, before the virtual disappearance of the worm as a result of the ecological transformation of Arrakis, suggests that the complicated internal chemical transformations also produced oxygen as a by-product rather than consuming it in the process of metabolism. Certainly it is well known that much of the oxygen on Arrakis after the original prehistoric catastrophe was derived from the sandworm, despite the apparent violation of the second law of thermodynamics. One authority termed the worm an "oxygen factory."

With only stunted sandworms or sandtrout to study at the present time, many of the questions concerning the worm may never be solved.


For many centuries it was believed that Sandworms were responsible for the desertification of Arrakis. However, many scientists later believed that sandworms were not the cause, but adapted out of that event.

According to Arna Satorinia, before becoming the gigantic water-aversive creature, the sandworm evolved from a small marine bottom-burrowing organism. The worm therefore was able to survive not only the cataclysmic event (49.7 Ma ago) that depleted all oxygen from the planet, but also the gradual evaporation of the original oceans. While most life had undergone mass extinction, the worm was given time to adapt, without being bothered by predators or competition for food.

By the time desertification was complete, the sandworm had become perfectly adapted to an arid environment, albeit now water-aversive.

According to W. N. Dragan, C. D. Umbo, and A. H. Hautan, part of the sandworm's metabolism produced oxygen, responsible for the gradual replenishment of oxygen in the planet's atmosphere.

Although the worm cannot withstand sudden contact with water, in theory, given some of the gradual changes, the sandworms would evolve once again into marine-dwelling creatures.[1]


The water needed for Pardot Kynes's terraforming project was lethal to sandworms; their death rate was much more higher than the rate of vegetation expansion. Combined with oxygen loss due to chemical reactions caused by the planet's high geological activity, the amount of oxygen dropped dramatically.[1] The last sandworm observed was seen dying in 10402.[2]

  1. 1.0 1.1 Arrakis - Oxygen saga
  2. Arrakis - Ecological transformation

See also[]

Further References[]

  • B. Gwever, "A Prologemena and Tentative Hypothesis Concerning Apparent Violations of the Second Law of Thermodynamics in the Production Rather than Consumption of Oxygen in the Metabolic Processes of Shaihuludata gigantica," Second Imperial Conference on Chemistry, Caladan.