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Comment by hammock | Hacker News Reader

Wouldn't the biggest factor simply be limited resources? The same reason why the average man was 5 inches shorter in 1750 than he is today.

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Actually, Foster's rule indicates that predation being the main threat leads to smaller animals, while the restriction of resources being the main threat leads to larger animals.

> The same reason why the average man was 5 inches shorter in 1750 than he is today.

This is more likely dietary changes than resource restriction—we may not have had industrial farming, but the average person wasn't starving either. But you need access to plentiful, high levels of protein to maximize your height advantage.

Foster's rule is actually the reverse of that.

Which can be seen intuitively because non-human predators pick off the weakest and smallest of the pack.

This depends on the size of the animals in question compared with the largest practical size for an animal in that environment. Large animals will get larger, because this improves their chance of fighting back against similar-sized predators (think lion vs. antelope). Small animals will get smaller, because this allows them to evade much-larger predators (think cat vs. mouse).

> But you need access to plentiful, high levels of protein to maximize your height advantage.

Hence a resource restriction?

Probably the same reason storms on Jupiter are larger than storms on earth.

You can't be bigger than your container.

Yes. That's what I'm getting at. In fact animal size and storm size are probably predicted by a power law curve to the surface area of the environment

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