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Old Jun 7 2020, 06:16 PM   #1
CuriousFlit
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Default Are Dragons Mesotherms / Photosynthetic? How much do they eat?

I know dragons are said to be warm-blooded, but they only eat about once a week (so once every 7 days or so since a Pern week = an Earth week) when fully grown right?

That seems like a surprisingly slow metabolism for a warm-blooded animal that big (even if half the length is tail), assuming they're purely warm-blooded. By Skies of Pern there are "six thousand two hundred and forty dragons, and half of them are brown, bronze, and gold". So I'm wondering if there's some trick engineered into them to help with getting that extra needed energy without plunging Pern into a famine trying to feed all those dragons.

They sure do like sunbathing whenever possible, so I'm wondering if that ties into it. Do they get some of their energy directly from the sun?

Has anyone figured out about how much dragons will eat per feeding, btw? I remember that big green from Skies of Pern and her rider saying that two felines will feed her for a week. I know the big cats keep getting called cheetahs or lions, so I just assumed they started out as normal cheetahs, but over time they got bigger and changed in body structure, which made them look more like lions.

So how much meat would you say you get off a lion-sized cheetah? That green was also big for her color, wasn't she?

I know dragons eat "herdbeasts" (cows? goats? sheep?) and wherries are said to look like turkeys (I assume wild ones except those that got domesticated) but are as big as ostriches. So how much would you get from an ostrich-sized turkey?

On that note, how do the dragons get their needed skeletal boron from their red-meat diet? Dragonlover's Guide to Pern says the boron from Pern's grasses ends up in the guts of livestock. Dragons eat everything from their kills, right?

If we consider that 9th Pass dragons (meaning dragons born during Bendon Weyr's 400+ years of isolation and inbreeding) are measured in meters and dragons of all other Passes from 3rd onward are measured in feet (that being their pre-programmed size), with Ruth being 20ft long (meaning if he wasn't neuter, he'd have been a small green)--

--And yes, I know this debate will probably go on forever lol :P

But I do have a reason for measuring dragons this way, see this post: http://forums.srellim.org/showpost.p...0&postcount=60

So about how much would dragons be eating? Breaking down their meal sizes by color, of course. I know a green certainly wouldn't have the same diet as a gold. I tend to use the population scale from the Pern wiki:

50% green
30% blue
15% brown
5% bronze
less than 1% gold
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Old Aug 8 2021, 06:09 PM   #2
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Default Re: Are Dragons Mesotherms / Photosynthetic? How much do they eat?

I very much doubt that Pernese Dragons are warm-blooded in the same way that mammals are on Earth. They would likely be closer to birds and dinosaurs, and may have used a system of thermoregulation based on their size, like some dinosaurs were theorized to do:

https://www.newscientist.com/article...ter-its-blood/

https://en.wikipedia.org/wiki/Gigantothermy

Basically, the larger an animal, the easier time it has maintaining its body heat.

In that case, they wouldn't need as much food in relation to their body size as say, a large mammalian carnivore like a tiger. Being flying animals, they would need more than a reptile like a crocodile, and probably could not go the months between large meals that crocs and large snakes are capable of.

The couple of herdbeasts a week seems reasonable, if we assume that "herdbeast" refers to a cow, with an average body mass of 750 kg (female) to 1100 kg (a steer, likely to be sent to the Weyr in tithe).

One study estimates that a T Rex would need about 140 kg of meat a day to stay healthy. If we assume Dragons are a similar size to a T Rex (between 5-9 metric tonnes) and that they eat the entire herdbeast, and, like most large carnivores, they usually eat as much as they can in a single setting, then a couple cows/week would be adequate. They'd actually be getting a bit more food/week than the T Rex would (about twice as much if they ate two large steers).

https://fivethirtyeight.com/features...-feed-a-t-rex/

Dragons spending a great deal of time just hanging out on their weyr ledges or sunbathing is likewise similar to the behaviour of other large carnivores. Lions sleep like 20 hours/day.
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Old Aug 9 2021, 12:01 AM   #3
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Default Re: Are Dragons Mesotherms / Photosynthetic? How much do they eat?

That sounds very reasonable, Violetlight.


The one thing we don't know is how going between affects the energy needs of a dragon, because there's nothing to compare with that on Earth. Gigantothermy is basic physics and would work the same on any planet.
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Old Aug 14 2021, 12:29 AM   #4
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Default Re: Are Dragons Mesotherms / Photosynthetic? How much do they eat?

Well ddepending on how much they go between, in Moret the one blue come back to Fort to each every day, and just for thought rember becuse Anne said so too, Also recall the feelines that Ted Tumberman,took had spotts, to a his youn son, but who knows, if he took a few other to try and crss breed, and his son wasn't around to see, just to keep this going,

Ruth is as a a as small or near as the orginal dragons, Sean saide a horns/runnerbeast, note, In DEnd of a TYYear that the green would be only twice a week and geting her own food at that., the day after hatting, note DE/RSR is my ref.

The sunning theyu store could be how they handle betwee.


Also the boran was not found in their gut, but changed so they wree found in the muscles of the one that addapted to pern grasses, for the First Hatching on Pern Dragondawns. I hope this from what I recal helps getting tired,.
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Old Aug 14 2021, 12:31 PM   #5
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Default Re: Are Dragons Mesotherms / Photosynthetic? How much do they eat?

Quote:
Originally Posted by granath View Post
That sounds very reasonable, Violetlight.


The one thing we don't know is how going between affects the energy needs of a dragon, because there's nothing to compare with that on Earth.
There was one fanfic series, "Dragonchoice", that theorized that going Between actually used a lot less energy than flying straight. This becomes very important in the last fic of the trilogy, where dragons lose the ability to go Between, and subsequently have to adapt to fighting thread without it. There are a *lot* more casualties, blues and greens are made the most important dragons due to their agility (with browns and bronzes basically regulated to firestone delivery), and the Pernese economy basically becomes centered around cattle ranching to a much larger extent than usual, just so they can feed the dragons more often. It's stated that with flying straight all the time, dragons need to eat daily instead of a few times a week.

https://www.dragonchoice.com/

It's only a fanfic, and obviously not canon, but it really makes you think about some of the details that were skipped over in Anne and her children's books.
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Old Aug 15 2021, 07:29 AM   #6
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Default Re: Are Dragons Mesotherms / Photosynthetic? How much do they eat?

Quote:
Originally Posted by Violetlight View Post
There was one fanfic series, "Dragonchoice", that theorized that going Between actually used a lot less energy than flying straight. This becomes very important in the last fic of the trilogy, where dragons lose the ability to go Between, and subsequently have to adapt to fighting thread without it. There are a *lot* more casualties, blues and greens are made the most important dragons due to their agility (with browns and bronzes basically regulated to firestone delivery), and the Pernese economy basically becomes centered around cattle ranching to a much larger extent than usual, just so they can feed the dragons more often. It's stated that with flying straight all the time, dragons need to eat daily instead of a few times a week.

https://www.dragonchoice.com/

It's only a fanfic, and obviously not canon, but it really makes you think about some of the details that were skipped over in Anne and her children's books.

I've read most of Dragonchoice. Life just got in the way before I finished the third one. I liked them a lot, so thanks for the reminder.
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Old Sep 16 2021, 07:38 PM   #7
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Default Re: Are Dragons Mesotherms / Photosynthetic? How much do they eat?

It may also depend on how large (that old argument) we're thinking dragons truly are. 40 feet vs. 40 meters is a big difference in feeding those beasts.
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Old Sep 17 2021, 09:32 PM   #8
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Default Re: Are Dragons Mesotherms / Photosynthetic? How much do they eat?

Quote:
Originally Posted by granath View Post
I've read most of Dragonchoice. Life just got in the way before I finished the third one. I liked them a lot, so thanks for the reminder.


I was using the site to learn how to run myJAWS my screenreader, better, I havn' did the first one, and reading with the screen reader I see I missed more then I thought, I got to finish Pt2 and Pt3 of that set, I have its bookmarked, I might just use it to help me master my problems with this. Just ssticking a reminder in here for my own ,, for its been a berry busy day. Now Back on topic: :o

The only two times I recall eating alot are K'lon's blue, and Jaxom's RRuth, off the top of my head, I don't have all my books in audio at my fingertips, at the moment.

I do also recall that Ramoth had a big meal six? then she flew and what happen with the holder, and she hadn't eatten before all the flying, she turn dull, note I think she had thesame before she and her rider 'time it between' and she was OK, sorry my mind sometimes get a head of my fingers.

I only have recall a bit of this, some of that, which which just is confusing some folks new or returning to the Mon.

I still haven't got the hang of JAWS my screen reader and how I see the board or links yet.
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Old Sep 17 2021, 11:49 PM   #9
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Default Re: Are Dragons Mesotherms / Photosynthetic? How much do they eat?

I had a hard time visualizing how much it took dragons to eat, that they couldn't breed herd animals fast enough. Being conservative of the 'two cows a week' and substituting for one since the dragons get smaller from gold to greens. That's 324,480 herdbeasts a year while using the 6,240 in dragon population from Skies of Pern. Otherwise 2 herdbeasts per week per dragon would be nearly 650,000 herd animals per year o_o

You have to factor in people eat them too, and losses from predators, natural disasters, and random health issues. Not to mention golds and their suitors blood and kill beasts when they rise to mate (granted, perhaps some dragons wouldn't mind eating these leftovers as their food quota for the week).

I also realize you can substitute wherries, ovines, caprines, felines, etc for feeding dragons but more would need to be eaten to make up for the meat weight of cows.

Bison in the millions used to graze the U.S. but they also didn't have to contend with Thread eating them and the grasslands too.

Interesting stuff to think about for sure

Last edited by Altair; Sep 18 2021 at 10:59 AM.
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Old Sep 18 2021, 06:07 PM   #10
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Default Re: Are Dragons Mesotherms / Photosynthetic? How much do they eat?

Math is one of my learning problems , but, Once they are fully grown its sounding l like with the felines from The Skies of Pern, One of them, would feed half of the Wyerleader's wing, and Tia's green had two, they sounded like a treet for them,, Lions are one of the 'big cats' and theand we don't know what type of feline Ted Tubberman took, from Red's report, for they were all mixed up, TThe one had spspots an but if they were like the 'lions; from Dragonseye / Red Star Rising which cccomes right after Dragonsdawn, they have been inerbreeding to stay alive, I am very sroy my mind is jumping around, But they were not Todds books They were on the Western Conternet ,, but who knows maybe he used it as his testing ground? and the ones their learned to do what was needed to live? I still have a fparts of hissolo work, that don't make a lot of seanse, But If the ones that were smart they would have used the cave to shelter in,, but with out grubs, which I deon't know how else they got ther, be ing so far from the rest of Pern, And Threadefall after the end of Todd's books, would have eeaten all the stuff? I haven't read more about it, They when back in The Skies of PePern, but still, I am just not to sure like I What the first Shunned person ddid once he was left at his stake. Note I am sory for my rambling, I haven't llisten to all the audio books Yet, so my memory is what I'm drawing on at the moment. PS I don't have Dragonsblod in audio anymore , my tape set is gone, can't find a another copy, I think I dammaged the CD that I had it on, so I am out of luck, Note I don't mind hisgoing two different POV End of two passes/interval , that is not what bbugs me, or a f a fire lizard with two oweners in two different times, so much, Or having a connection with the pass, Anne used that with Lessa so I can live with that, Its Or a hhint of using between time to recover and grow up, and a different point of view, What gets me is, his over use of 'timing' to savefolks, and in between note I am t trying to put down my feedback on why I also thinkk its not so right with his writing as a, dragons stay alive, in the only way I can. I hope you folks can forgive me for if I have gone off topic I used the information from my memory which has Todd's book his first one, which helps explan some stuff that is found later in Benden Wyer. which is also how I am trying to write my feedback, The time jumping in the later books, has added more twist and turns then a berrow of tunnel-snakes, note I got that idea from aDuke of Hazzard MMoMovie , no infringement ment the orginal was a bucket of them, and pern's ones are a lot bigger, and have more parts to fit in there.
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