Mountains tend to be narrower at the top than they are at the bottom – otherwise they’ll
eventually fall down – but that doesn’t mean that mountains are always SMALLER at
the top. Because, what matters to most land creatures is the amount of land; that is,
the surface area, not the volume – unless you’re a mining company that plans to pulverize
the entire mountain into smithereens. Then volume matters.
But to the rest of us, we care about surface area – and surprisingly, the area of land
on a mountain doesn’t necessarily get smaller as you go higher up the mountain – especially
when that mountain is part of a mountain range, as mountains tend to be.
Simple, lone mountains with shapes like cones or spikes or inverted parabolas do indeed
have less surface area the higher up you go, though a parabolic mountain has a lot more
area high up than a spikey mountain. And broader, flatter, mountains can actually have MORE
area the higher you go up, at least until you get to the very top. These mountains do
get skinnier as they go up, but they get flatter so much faster than they get skinnier that
from the perspective of available surface area they’re bigger on top than at the bottom!
And when you put mountains together into RANGES, it’s even more complicated. Some ranges
have LESS land area the higher you go up, some have MORE area, some have more and then
less, and some actually have more area at both the bottom and top and less area in the
middle!
In fact, if you do a survey of mountain ranges the world over, you’ll find that only around
a third of them have a constantly decreasing amount of land the higher you go, and the
rest exhibit one of the other weird “top-heavy” options.
In other words, despite appearances and as odd as it sounds, MOST mountain ranges are
bigger near their tops. Which has interesting implications for any land-dwelling creatures
that might want to move their homes and businesses up or down mountains, if, I don’t know,
the climate changes or something.
And one more weird fact: a perfectly hemispherical mountain, while impossible in reality, has
just the right shape to get skinnier at the same rate that it gets flatter, so it has,
amazingly, the exact same amount of area at every elevation. The same math also means
that if you evenly slice an orange, each piece will have roughly the same amount of skin
– but different amounts
of fruit.