need help on predator prey cycles

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madd0ct0r
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need help on predator prey cycles

Post by madd0ct0r »

Is there a way to predict them based on the rough current point of the system?
Is there a way for an intlligent predator to mediate them?

for my stgod game faction -
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madd0ct0r
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Re: need help on predator prey cycles

Post by madd0ct0r »

Rest of post was cut off.

This is for my stgods faction who are apex carnivores in an ice age tundra setting. North American nomads following herds of semi-domesticed mammoth, musk ox, caribou and coastal foods.
Adult females weigh 300kg, males a little less. Based off polar bears they need to eat 1kg of fatty meat a day. Based off very rough area and energy calls, they can't support 100,000 population without eating most of the herbivore population per year (at least in energy terms). I've chosen a yearly birth rate with kits being fully grown in seven years. Is this flat out impossible?
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Ziggy Stardust
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Re: need help on predator prey cycles

Post by Ziggy Stardust »

It's not super clear what you are asking. What are you trying to predict? Relative population sizes? Population dynamics over time? What do you mean by 'mediate' in this context?
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madd0ct0r
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Re: need help on predator prey cycles

Post by madd0ct0r »

well, the classic tundra predator prey cycle has a large wave pattern.
Image

Since I'm trying to write about a faction of artic predators with a large population, I'm worried this is something that I should take into account of in the stories. It's a good plot hook.
On the other hand, a more stable population is easier to keep track of and for other players to deal with. In which case, the actions that an intelligent, nomadic herding race would take to avoid that cycle would be an interesting thing to write about and probably a good plot hook.

I know as a writer I could choose either, but I like to chase the implications and believe they make for a better, more coherent story.
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Alyrium Denryle
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Re: need help on predator prey cycles

Post by Alyrium Denryle »

Whose cycles usually deal with a single preferred prey item that makes up the bulk of a predator's diet. If they feed on a variety of prey species, the populations will still cycle, but the amplitude wont be as large unless the stars align and it is a bad year for all their prey species.

That said, population size will never be large. The scenario you have is pretty much impossible. The arctic is just not productive enough to support terrestrial prey populations large enough to support 100k people that mass in at 300 kg each.
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madd0ct0r
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Re: need help on predator prey cycles

Post by madd0ct0r »

Well its not true arctic. Nunavut. Canadian shield.
I made some rough notes here
https://docs.google.com/spreadsheets/d/ ... cslist_api

Suggests the population eat 32% of the available hwrbivore energy each year, which might work but does seem prone to chaotic fluctuation.

Main prey are semi domesticated mammoth, musk ox and caribou. Birds whales and small things like rabbits also feature.
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Re: need help on predator prey cycles

Post by Simon_Jester »

On a side note, it's a fantasy setting. If actual magic is required to make this work because it's impossible in real life, that's not necessarily a problem... but it is far more interesting to go down that road when you have a good idea of exactly what magic is called for.
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Re: need help on predator prey cycles

Post by Sea Skimmer »

You are not going to support a huge predator population off the Tundra. Polar bears spend an awful lot of time sleeping, otherwise I suspect their energy demands would be much higher even with that fiber optic like fur heating system they have. But do they have any technology at all? The ocean even in the far north can be incredibly productive. For a STGOD I think it would more then suffice to say they whale and seal as much as they can in summer to mitigate overkill of the land animals.
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Alyrium Denryle
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Re: need help on predator prey cycles

Post by Alyrium Denryle »

madd0ct0r wrote:Well its not true arctic. Nunavut. Canadian shield.
I made some rough notes here
https://docs.google.com/spreadsheets/d/ ... cslist_api

Suggests the population eat 32% of the available hwrbivore energy each year, which might work but does seem prone to chaotic fluctuation.

Main prey are semi domesticated mammoth, musk ox and caribou. Birds whales and small things like rabbits also feature.
32% is in Oh Fuck NO territory, no matter what ecosystem they are in unless their only prey items breed psychotically quickly.
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madd0ct0r
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Re: need help on predator prey cycles

Post by madd0ct0r »

which, being large mammals, they won't. Fuck.

Time to start prepping the great famine storyline :)
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Ziggy Stardust
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Re: need help on predator prey cycles

Post by Ziggy Stardust »

madd0ct0r wrote:which, being large mammals, they won't. Fuck.

Time to start prepping the great famine storyline :)
I mean, you've already described this as a nomadic population. Like any nomadic population, they wouldn't be spending the entire year in a single unproductive environment like the arctic. All you need to do to make this more feasible is make it clear that there are subarctic/temperate regions that these populations inhabit for some portion of the year, and that this 100,000 population is distributed across a WIDE geographic region (like, Russia-sized, or whatever is appropriate for your fictional geography) as opposed to being a single cohesive unit.
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Re: need help on predator prey cycles

Post by Simon_Jester »

madd0ct0r wrote:which, being large mammals, they won't. Fuck.

Time to start prepping the great famine storyline :)
Or, well, break out the magic. You are fully within your rights to do that, after all. Maybe the Canadian Arctic of our game is more productive somehow or for some reason, just as the Colorado Plateau is a necromantic hellscape hotter than Death Valley.
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madd0ct0r
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Re: need help on predator prey cycles

Post by madd0ct0r »

I already did :) those calcs were for a warmer place than Nunavut. Plotwise it works becyase the last two decades the hyenorks have been at war with each other and for decades before that crashing against the elf defenses.

It fits that their growth in population is limited mostly by raiding and killing each other and their neighbours. There's been a good last decade with corresponding population boom. It'll be a good plotline promise. Although you may get invaded next winter.
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Re: need help on predator prey cycles

Post by LaCroix »

Makes sense.

In an environment with limited ressources that also prevents agriculture, and demands nomadic tribes, a high amount of tribal warfare or expansionist warfare into better foraging grounds is to be expected. As soon as the population spikes, tensions increase, keeping the population down.
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