Aug 7 2013 10:00am
Science of Future Past: Dune (Part 3)

Dune Sandworm

When I sat down to think about which bits of science I wanted to highlight in Frank Herbert’s Dune, one of the first things I thought of was Sandworm biology…

This is my favorite scene from Dune:

“Out of the sand haze came an orderly mass of flashing shapes—great rising curves with crystal spokes that resolved into the gaping mouths of sandworms, a massed wall of them, each with troops of Fremen riding to the attack. They came in a hissing wedge, robes whipping in the wind as they cut through the melee on the plain.

Onward toward the Emperor’s hutment they came while the House Sardaukar stood awed for the first time in their history by an onslaught their minds found difficult to accept.”

Whose mind could accept shai-hulud; the Maker; Grandfather of the Desert; the Sandworm of Arrakis?


Much has been written on the great sandworms, though perhaps no one understood them better than the great Pardot Kynes, first Imperial Planetologist of Arrakis.

But even after reading Dr. Kynes’ report, “The Ecology of Dune,” I’m left with a few questions about the life cycle of the Maker.

Since I’m not as well versed in Dune-lore as many people on this site, I’m hoping that some of you can help fill in the gaps of my knowledge.

The Basics

Here’s the key excerpt from Dr. Kynes’ report:

“Now they had the circular relationship: little maker to pre-spice mass; little maker to shai-hulud; shai-hulud to scatter the spice upon which fed microscopic creatures called sand plankton; the sand plankton, food for shai-hulud, growing, burrowing, becoming little makers.”

For those of you who are more visually minded:

Dune Sandworm Life Cycle Pardot Kynes


So now we’ve seen the life-cycle, as explained by Dr. Kynes. So here are my two questions:

  1. Where does sand plankton come from? Is it self-propagating?
  2. What triggers the transformation of sand plankton into little makers?

If you know the answer(s), please leave it in the comments! Please specify the source where you’re getting the information from. (A canonical book, something you saw in a movie, something you thought of on your way to the store, etc.)

Dr. Lee Falin is a Bioinformatician, the host of the Everyday Einstein’s Quick and Dirty Tips podcast, and the author of the “Science Fictioned” series, in which he takes scientific research articles and turns them into science fiction and fantasy short stories for middle grade and young adult readers.

Derek Broughton
1. auspex
Where does sand plankton come from? It's circular - stick a circle on the bottom of your diagram for "eggs". I think it might be possible that the sand-trout are the egg-layers, rather than the sand-worms, but since Kynes has described a biology not inconsistent with Earth biology, it only seems reasonable to use it.
Jeff Weston
2. JWezy
Which then begs the question, what does sandworm sex consist of? I stand
awed for the first time in my history by an onslaught my mind finds difficult to accept.
Derek Broughton
3. auspex
Just like earthworm sex, I imagine: they slither along each other in opposite directions, each depositing sperm in/on the other, and both set about laying eggs.
Thomas Thatcher
4. StrongDreams
One thing that is missing is an energy source. On Earth that is usually the sun, occasionally other compounds that can be reduced to a lower energy state (hydrogen sulfide, Iron (III), etc). It's never specified on Dune what that is. It can't really be sunlight, since the sand plankton must be burrowing creatures (else the worms wouldn't burrow). Maybe heat somehow? I'm not sure how that would work biochemically.

Also, if the sandworms eat sand plankton, why would they need 3 foot long crystal teeth sharper than steel?
Constance Sublette
5. Zorra
They're called sand fleas on the beaches of Southern California ....
Eugene R.
6. Eugene R.
Bit of an incestuous food chain, no? Which brings up the question of just what kind of "plankton" the little sandies are, phyto or zoo? Since they are at the base of the food column, I would assume that they are phyto (plant) plankton, generating food calories via photosynthesis. But that would mean that Shai-hulud would likewise be a plant, like the scariest zucchini in the galaxy. And if they are zoo (animal) plankton, what do they eat? The spice? Which is just sand trout (little maker) droppings? Which in turn is ... digested sand plankton? Or do sand trout have another food source? I suspect that the sand Ouroboros is twisting 'round to bite its own tail.
Eugene R.
7. Anthony L
Dune has no virtually no plants, which means oxygen production comes from elsewhere for the planet to be habitable. If I remember correctly it is never fully explained, only postulated (can't remember which book mentions this), to be a by-product of the sandworms' metabolism.

Spice blows release large amounts of gas and spice, so the whole system is self-propagating. It would explain why spice on the planet's surface is quickly attacked by shai-hulud: protection of the food supply.
Eugene R.
8. RedMaigo
There is a book called The Science of Dune by
Sibyelle Hechtel. It has a chapter on the biology of sand worms.

Unfortunately, I have never read it. However, I found a couple of posts examining, and even refuting, some of the sandworm biology in Hechtel's book.

If you don't want to buy the entire book, you can purchase the Biology of the Sandworm chapter at the below link for about a dollar.
Brian R
9. Mayhem
Well, one factor everyone seems to not be considering - Temperature.

From the appendix:
First, the climate: the sand surface often reached temperatures of 344° to 350° (absolute). A foot below ground it might be 55° cooler; a foot above ground, 25° cooler. Leaves or black shade could provide another 18° of cooling. Next, the nutrients: sand of Arrakis is mostly a product of worm digestion; dust (the truly omnipresent problem there) is produced by the constant surface creep, the “saltation” movement of sand. Coarse grains are found on the downwind sides of dunes. The windward side is packed smooth and hard. Old dunes are yellow (oxidized), young dunes are the color of the parent rock—usually gray.

Even if we're talking Fahrenheit temperatures, thats 170-175C, which is pretty damned hot for a desert, and would have interesting effects on the sands.
Given the sands are described as Yellowing with age ... yellow tends to be a result of iron impurities mixed in with the quartz, which may affect melting points. Grey tends to be more granite based, implies a lot more feldspar. Both would have ancient volcanic origins.
One interesting thought - the Sandworms tend to bring lightning strikes with them into an area, a result of static electricity discharging into the air ... well quartz develops a piezoelectric charge with mechanical stress, so that would be a logical follow on - 400m worth of sandworm would be one heck of a mechanical stress. I suspect the worm can use that electricity within its biomechanisms.

Wild speculation time - Feldspar is Potassium/sodium/calcium with aluminium, silicon & oxygen. How about the sandworms evolved to process silicon and aluminium oxides internally, using mechanically generated electricity to provide the energy for the necessary heat. Cryknives are transparent shards of the teeth, well Aluminium glass alloys are relatively transparent and extremely durable (Star Trek's Transparent Aluminum turns out to be suprisingly plausible).
The burrowing action is to maximise the electric potential that can be drawn out of the sands, hence the fact that the worms are generally only found in the deep deserts where the sands are likely to be more mobile. The little deserts get little worms as there isn't the resource supplies they need to grow larger.

No idea on food, but perhaps the sandplankton may contain (or metabolise) certain trace elements that are needed to ensure the creation of the correct alloys as part of the worm growth cycle. That plus the raw sand gives all you need. A partly carbon, partly silicon, partly aluminium creature. Free water would be toxic, because it would interfere with the internal chemistry to a severe degree and trigger a fiery reaction, unless bound up in alcohols or acids. The Water of Life would be a highly peculiar metabolic poison containing a range of alcohols and aldehydes, the smell of cinnamon coming from
Acrolein or Cinnamaldehyde.
p l
10. p-l
@6: Not necessarily. We now know that there are at least a few photosynthesizing animals on Earth. It's possible that the sand plankton could photosynthesize but lose that ability in later life stages, or that they're symbiotic with some photosynthesizing algae or bacteria.
Derek Broughton
11. auspex
@9: of course we're not talking Fahrenheit. It tells you: "344° to 350° (absolute)." "Absolute" means °K, and 273K is the freezing point of water. 344-350, then, puts it in the realm of 70+C, 160F-170F — extremely hot, too hot to survive in without protection — not too hot to survive a day or two with stillsuits.

The rest of your speculation is pretty good!

@4: I don't think it follows that the sand-plankton can't be photo-synthesizing. Spice-masses are, iirc, greenish, implying photosynthesis. Sand-worms would still burrow, whether they need to cannibalize the plankton or not - they need to get out of that extreme heat. Plus, just because worms do eat plankton doesn't mean that's their only source of food - clearly they eat anything organic, and a few things inorganic! Whether they can digest it all is likely to remain unknown.
Marc Gioglio
12. Fuzzix
First, the climate: the sand surface often reached temperatures of 344° to 350° (absolute).

When I read the above sentence, I took (absolute) to mean Kelvin (°K), thus roughly 71°C to 77°C or 160°F to 170°F.
Eugene R.
13. a1ay
Where does sand plankton come from? Is it self-propagating? What triggers the transformation of sand plankton into little makers?

Sand plankton need not be a single species - plankton on earth is a generic term for "tiny little animals and plants living in the water column", and that includes the larval forms of much bigger animals. So I'd expect that "sand plankton" is just the catch-all term for "little beasties on or near the sand surface" and that includes proto-little makers which grow up to be little makers, as well as all kinds of other stuff that doesn't. Some of it is autotrophic (it makes its own food, by photosynthesis or in some other way) and some is heterotrophic (eats plankton).

Possible other energy sources:
chemosynthesis.We don't see any volcanic activity on Dune but maybe there is some. Volcanic vents in the bedrock, submerged under hundreds of feet of sand, pumping out hydrogen sulphide, could be a desert equivalent of the black smoker vents on earth's deep oceans, feeding colonies of chemosynthetic sand plankton. That's why the worms have to burrow: it's where their food source is. Maybe that's where the rest of Dune's (weirdly impoverished) ecosystem is too - living at the bottom of the dust seas, like Niven's Martians.

Or, since we mentioned the dramatic heat difference in 9: thermocouple generation. Maybe some of the sand plankton isn't little blobs so much as long strands of fibre, a few metres long, exploiting the heat difference between its ends to generate an electrical current which drives formation of glucose (and production of oxygen) along exactly the same reaction pathways as in chloroplasts. Thermoelectrosynthesis! Nothing lives on the sand surface because it's too hot and UV-drenched for anything except a thermophile bacterium, but two or three metres underground and invisible from the surface there are great mats of fibrous electrosynthetic vegetation, surrounded by swarms of grazing sand plankton.
Eugene R.
14. a1ay
Which then begs the question, what does sandworm sex consist of?

God help me, but I am now stuck with a vision of a sandworm sliding past on the surface, its Fremen riders standing on its back with hooks in place, and stuck on one of its tail segments a large sticker reading:
Eugene R.
15. a1ay
Third possibility for Dune ecosystem, and this is completely unsupported by the books but is rather fun:

There is, actually, an environment on Earth that very closely resembles the surface of Dune. It's largely barren, with very little primary production, but a surprising number of large creatures with huge pointy teeth.

I'm talking about the aphotic zone - the deep sea bed.

The animals down there (and let's ignore the black smoker vents for the moment) live on what's called "organic snow" - dead matter drifting slowly down from the life-rich waters above. Things like gulper eels ( prowl around, looking for big bits of carrion - and they have vastly expandable stomachs and huge teeth, because when they find that rare goldstrike, they need to eat it all, because the next one won't be along any time soon.

So, here's the suggestion: where is the primary production on Dune? Where's the rest of the ecosystem? Where, in fact, is all the oxygen coming from?
Look up.
Dune has an aeolian ecosystem. Miles above the barren surface of the planet, photosynthetic aeroplankton are drifting, kept afloat by bladders of hydrogen (produced as a byproduct of their metabolism) and great filmy medusae, animals hundreds of metres wide but as insubstantial as aerogel, are swimming slowly around feeding on them.
When they die, they gradually drift down as their hydrogen sacs deflate, and eventually land on the desert surface, where they are scavenged by the sandworms.
No human's ever bothered to look, because no one is interested in the high atmosphere - it's too high for ornithopters and too low for starships. And from orbit, the shoals of aeroplankton are indistinguishable from Arrakis' perpetual dust storms.

(Idea stolen from Arthur Conan Doyle, "The Horror of the Heights", which you should read.)
Dave Newton
16. DaiKiwi
I'd refer to The Dune Encyclopedia by Dr Willis McNelly, which was authorised by Frank Herbert, and is canon up to God Emperor. The relevent entries are on Arrakis and Shai Hulud. Sadly, the book is long out of print and likely to remain so given the prequels/sequels produced by the Herbert estate. If you find one, buy it. It makes a great companion to the first four books.

It is speculated that the great worms are evolved from protochordata deep-sea burrowing worms during the desertification of Dune, beginning 49 Mya. The entry for Shai Hulud gives more information in the life cycle, and a more detailed illustration, and details on metabolism. A condensed quote is below:
After fertilization the male deposited the spice fiber egg case into sand. 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 travelling 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

When the pressure built sufficiently there was a powerful explosion 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. During the blow many sandtrout in the immediate vicinity were killed. 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. Changes in metabolism began so that water gradually became toxic and rudimentary autotrophy developed

The premetamorphic stage consisted of joined sandworms each capable of metamorphosing into an individual sandworm segment The metamorphic process took over 1,050 years. 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.

[In the adult form] male worms 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.

METABOLISM OF THE ADULT 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 dnve 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 cupricyanide compound, the reduced form of which accumulated in the worm body. The electron donor was probably SiO2. 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, butyric acid, propiomc acid, acetic acid, and formic acid Excess gases not utilized for nutrients were literally ignited by the heat of sand travel.

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