Dragon Demographics
Over anything to do with dragons lies the guiding hand of Kitty Ping. These are not natural creatures, they were designed. They are her masterwork. It should be remembered however that she died before ever seeing a dragon, before the colonists even considered moving to the Northern continent.
If dragons were natural creatures, they would be the top predator on Pern, their numbers only limited by the availability of food. Humans would be food, and would be unlikely to survive against them except by wiping them out. It was therefore vital that dragons should be made symbiotic, unable to survive without humans. Thus dragonets are flightless, helpless creatures that must find a human partner or die. This symbiosis creates another problem. Dragonriders love dragons. Left unchecked, they might allow the dragon population to grow to the point where the entire economy was geared to feeding dragons. So how can the dragon population be limited?
- Telgar Weyr just before Second Pass had six queens (1), which was considered quite enough.
- Ramoth only allows two junior queens in Benden Weyr, though there is room for four (2).
- 'Oldtimer' High Reaches had four, but three of these were old and near the end of their reproductive life, a fourth (Segrith) was necessary to keep the Weyr going.
- There were 17 Oldtimer queens (3) in total, average number per Weyr 3.4. Most of these would have been old queens, hatched in the pre-8th Pass expansion fifty Turns before. More on this later.
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| Cover for the first Pern story |
Dragons always suicide when their riders die, and there is no instance I can recall of dragons dying naturally before their riders though they do get old. The life span of dragons is thus tied to the life span of their riders.
The colonists were screened for genetic defects, so the Pernese started with a 'clean slate'. One colonist was in her eleventh decade and still active (Cherry Duff in Dragonsdawn). Against that we have to place the lack of technological medicine and the periodic diseases and plagues, though we can ignore infant motality.
"...most dragonriders live to their tenth decade or better." (Falloner, MasterHarper Ch6)
Four score Turns and ten? If we assume dragonriders impress at 15 Turns old, then we have an annual death rate of 100/(90-15) = 1.3% for dragons. To that we have to add fatal accidents during training: Todd Johnson in DLG says this is around 1-2 per hatching during a Fall, less during an Interval.
"We keep replacing the old ones who die off. Benden's at full fighting strength" (Falloner, Master Harper Ch6, 2462)
So what is 'full fighting strength'? Todd Johnson in DLG thinks 360, and that figure when applied below gives the 'right' answer. Against that:
Robinton wondered too. Over three thousand strong the six Weyrs had been at the end of the last Pass. Now, unless he miscounted, there were barely three hundred. And not all of them able to fly Thread. (MasterHarper, Ch18, early 2490s)
...and F'lar also seems to think 500 is the proper figure.
I suspect they've been counting weyrs. Benden and Fort can indeed accomodate 500 dragons, but the five Weyrs that came forward had 1800 dragons - 360 each. My feeling is that 500 is only the right number at the very start of a Pass.
| Nemorth | |||
|---|---|---|---|
| Clutch | Turn | Eggs | Age |
| impression | 2465 | - | 58 |
| 1st | 2472 | 20 | 51 |
| 2nd | 2479 | 19 | 44 |
| 3rd | 2488 | 24 | 35 |
| last | 2505 | 11 | 18 |
Here is the data for Nemorth from MasterHarper. The last column is the age of the rider at First Fall (2508).
It is my impression from MasterHarper that these were Nemorth's only clutches: she came into season more often but either Jora paniced and put her off (pre 2472) or she gorged on her kill and failed to impregnate (pre 2488).
Suppose Benden had 360 dragons in 2465. Falloner thinks this has been a stable population, so 1.3% of the riders will die each Turn. Over 43 Turns that's 56% of them. So of that 360 there are about 158 left by 2508, all 58 or over.
From Nemorth allowing for a ½ loss from training per clutch we have 20+19+24+11- 2=72, all 51 or under. Total 158+72 = 230. (4)
In 2479 twenty-four Riders caught a 'fever' and at least twenty died. That is the only time such an event is recorded, so if we count it as 'extra' then 230-20 = 210.
That's above the Dragonflight figure of 172 dragons that flew First Fall, but closer to the '200 dragons' number quoted in Dragonflight. This discrepancy can be accounted for by there being two dozen or so riders/dragons that are like C'gan/Tagath too old to fly Thread.
The observant will by now have noticed an anomaly. I think there were barely 200 dragons in the early 2490s, Robinton thinks there were barely 300. Well, as all Real Scientists should I'm going to ignore that inconvenient paragraph.
"...Nemorth should have been mating twice a Turn for the last ten." (F'lar, Dragonflight)
Is F'lar correct? If Nemorth added 20 clutches at her average size of 18, that would be (18*20)-(0.5*20) -10 = 340 eggs, bringing Benden up to 210+340 = 550. That is oversize, but oversize is needed for a Weyr at the start of a Pass.
In any case, dragon numbers were falling when they should have been rising. Something had gone seriously wrong.
My feeling is that one queen per Weyr during Intervals is normal. This was not risky, with six Weyrwomen at separate locations disease and accident were most unlikely to catch all of them. When a Weyrwoman died she would be replaced at the next queen hatching.
For Benden Weyr to continue this tradition was madness, but the Eighth Pass Benden Weyrleader that Lessa met knew that Benden would survive - from Lessa! It is possible that he deliberately destroyed any records referring to other Weyrs, leading weyrfolk to think that they didn't need them.
| Ramoth | |||
|---|---|---|---|
| Clutch | Turn | Eggs | Queens |
| impression | 2505 | - | - |
| 1st | 2508 | 41 | Prideth |
| 2nd | 2509? | ? | Lamanth |
| 7th? | 2512 | ? | Wirenth |
| 9th? | 2513? | ? | Ralenth |
| 12th? | 2515 | 38 | Arwith |
| 16th? | 2518 | ? | - |
Ramoth reverts to 'normal' behavior and starts to produce big clutches and gold eggs. Her clutch sizes are not unprecedented, Red Star Rising records a 51 egg clutch just before Second Pass.
In Dragonquest Mnementh remarks (Ch3) that young Lamanth is 'flying well'. She comes from Ramoth's second mating(5).
There are three queens at Benden, so there is an unnamed one to fit in somewhere - between 2509 and 2512 perhaps. Subsequent queens were transferred to Southern Weyr such as Wirenth, hatched three Turns before her death in 2515.
Ralenth could fit in any time, but I assume hers to be a later impression as her rider Vanira is junior to Brekke. Subsequent to the fateful mating flight at High Reaches Vanira is passed over for weyrwoman in favour of Pilgra, this may have been political or more simply it may have been that she was actually junior to her.
Talina's Arwith is hatched from the egg that is stolen in The White Dragon(6)
It is possible for any of the queens after 2511 to be daughters of Prideth of course apart from the one in the 2515 clutch.
...Ramoth's thirty-fifth - especially as this clutch included a queen egg, the first in twelve seasons. Even so, the great queen rarely laid fewer than twenty eggs and this clutch, appropriately, numbered thirty-five. (All the Weyrs, Ch 11)
35 clutches in 21 Turns (2508-2528), 1.6 clutches per Turn. There are plainly a lot of unrecorded clutches missing from the list, so I've guessed at when they might fit in by spacing them evenly.
Dragon gestation times are in a Teaching Song:
Count three months and more,
And five heated weeks,
A day of glory [...]
- Dragonflight
210 'old' + 72 'new' = 282 dragons at Benden by Second Fall.
Ten turns later 47 more 'old' have gone leaving 163+72 = 235.
Ramoth's clutches are highly variable (<20-41) but let's suppose an average of 30, or 28.5 allowing for training accidents.
10*1.6*28.5 = 456.
Prideth died in 2515. Vanira's queen became mature in 2516, Lamanth in 2512. So by 2518 they have contributed 8 Turns worth of eggs. Let's assume they are not quite as productive as Ramoth, adding 50% to production = 684. So now we have 235+684 = 919 dragons! And there is another pre 2515 Benden queen still unaccounted for.
With no need any longer to limit mating flights to keep the dragon population down to that which the existing Weyrs could accomodate, [...] (Renegades, Ch14, 2522)
How mating flights are prevented is not said! I have this vision of Lessa telling Ramoth 'not today dear, I'm boiling numbweed'... By 2524 there are two extra Weyrs, Southern and Eastern, enough to absorb the overflow.
Let's return to the Oldtimers. Before the Red Star approached for Eighth Pass there were in my model six queens of varying ages, one at each Weyr. In the ten Turns or so before the Pass this number rose to around twenty. By the end of the Pass there would have been fourteen queens aged 50-60, two over 60 and four hatched at various times during the Pass.
Of course, thought F'nor, the Oldtime queens didn't produce large clutches like the modern queens, nor many golden queen eggs. Come to think on it, only three queens had been hatched in the Oldtime Weyrs since Lessa brought them forward. (Dragonquest, Ch1)
F'nor implies that there is something wrong. What I think he fails to see is that the Oldtime queens have settled to just replacing losses. Three queen eggs in seven Turns is actually more than are required.
"...All old queens, well past their prime. I doubt Loranth will rise more than once. The clutches at High Reaches have produced only one queen since they came forward." (F'lar, Dragonquest, Ch10, 2515)
By 2515 the fourteen queens are at minimum 50+7 = 57 turns old, so this would seem to be the dragon equivalent of menopause. Nemorth managed a small clutch and a queen egg at age 40.
In 2518, ten Turns into the Pass, the fertile queens are:
Ramoth plus four known surviving descendents, two at Benden one at High Reaches (Ralenth) and one at Southern (Belgjeth).
Perhaps two Oldtimer queens hatched late in Eighth Pass.
Three descendents of Oldtimer queens, one at High Reaches (Segrith) and one at Fort (Selianth). The third might be Mirath at Ista.
Total ten.
Casualties
Is the casualty rate higher than the stories would indicate? A hint that this might be the case is in the parallels made (by Todd more than AMC) with fighter pilots in World War One.
Why isn't this reflected in the stories?
To be cynical, the Weyrs and those in the know would have a strong motive for keeping quiet - they won't get volunteers from outside the Weyrs as candidates otherwise.
It is also likely that the casualty rate drops off steeply with experience. We don't read of any leaders being killed in Threadfall because Thread unlike human opponents is uniform, whereas an ace fighter pilot is always at risk - from other aces.
DLG (p40) says a queen rises two to three times a Turn with a clutch producing between 10 to 16 eggs. This is unfortunately one of those DLG facts that don't make sense!
2.5 * 13 = 32 eggs per Turn. It doesn't match the evidence, which suggests that queens rise less often but have bigger clutches. Nemorth had bigger clutches than this, and as noted above Ramoth doesn't rise as often.
Dragons that hatch also die. At this rate with 20 queens there would be 1.7 deaths per day. Since all dragons are aware of and are upset by the passing of one of their number, even their short term memories are going to have trouble coping with that.
The frequency of Threadfall is considered on another page. From that
If in Eighth Pass there were 20 queens and 2160 dragons, then to counteract the natural death rate each queen needed to produce (2160/20)*(1.3/100) = 1.4 eggs per Turn. 2.5 clutches each losing 1-2 from training accidents is 3.75 per Turn. Total 5 eggs per Turn.
The rest of the eggs are replacements for dragons/riders killed or maimed by Thread. That's (32-5)*20 = 540 per Turn. So the number per Pass is 540*50 = 27000.
The number per Fall is therefore 27000/14040 = 1.92.
That seems way too high. The First Fall of Ninth Pass had one fatality. Other narrated falls have serious injuries but none permanent. Ramoth's frequency, 48 eggs/Turn, would be worse.
If Passes started with 500 dragons per Weyr but the normal population was 360, does this give us an indication of the novice casualty rate? (500-360)/500 is 28%.
So let's try 28% novice casualties plus another 5% from older riders, about a third in total. That requires 50% more eggs to make up. With clutches of 20, that means a mating flight every 6 Turns for a fertile queen, and one permanent casualty every 10 Falls.
In 2518 with only ten fertile queens mating flights are required every 3 Turns for replacement purposes, plus some for aging Oldtimers.
Conclusions
Kitty Ping's controls are:
- Humans are sociable creatures, and being derived from fire lizards so are dragons. They will be living in communities. She therefore set queens to become uncomfortable if forced to share with more than one other queen, and besides complaining to respond by not laying more gold eggs.
- Immediately before and during a Pass this instinct was partially suppressed to allow more queens to live together.
- Queens on a mating flight will attack other queens. During a Pass there is a better than even chance per Turn that two mating flights will take place on the same day, so Weyrs need to be widely spaced to avoid disaster.
- Unchecked, queens rise around every eight months.
- The normal clutch size is around 20. The specific conditions that herald the start of a Pass trigger queens to produce larger clutches, more gold eggs. 'Dragons prove', as the song says.
In Ninth Pass the Oldtimers were a vital stop-gap, but their age distribution will result in most of them dying about halfway though the Pass, and becoming too old to fly Thread earlier. This is not something Kitty Ping allowed for! The younger queens will therefore need to rise more frequently than normal to keep numbers up later on. It thus makes good sense for Ramoth to keep going for a while.
Acknowledgements
Thanks to Sariel for her datechart and Hans van der Boom for error correcting. Any remaining errors are mine, any remaining inconsistencies are the author's!
Footnotes
- Red Star Rising Ch3 [Back]
- Dragonquest, Ch1 [Back]
- Dragonflight, T'ron on arrival [Back]
- Calculating on an annual basis will give a different figure - my spreadsheet says 235. This is because with a declining birth rate the population distribution is skewed towards older dragons. [Back]
- This is in Ch3 of the US edition of Dragonquest but not the UK edition.[Back]
- Skies of Pern: Lessa blinked. "Oh! Talina's Arwith says that T'gellan is going to Landing, too."[Back]
