Wherein I begin to discuss the matter of animals.

One of my favorite ideas that I came up with has to do with completely separate evolutionary tracks on the northern and southern continents. To summarize and over-simplify: the northern will be twos, and the southern will be threes.

The northern continent is where my civilized humanoid biped species is going to develop (the one that speaks that language). They, along with pretty much all of the animals who evolved on that continent, will have either two, four, or eight limbs/digits per limb if relevant, bilateral symmetry, etc. So my elf people (they have pointy ears, it is easy to just call them elves), they have two arms, two legs, four fingers/toes per hand/foot, two eyes, a nose with two nostrils, a mouth, two ears.

There will be quadripeds too, of course, of various kinds, and large insects of various kinds which I have not really thought too hard about yet (and when I say large I do mean large). Lots of antlers, which I shall cover at a later date.

One major impact that this will have on the culture is that their numerical system will octal, not decimal. This could, likely will/would, have a strong impact on their technological advancements in the realms of computing.

And then there is the southern continent, where instead of twos, there are threes. Animals will either have bilateral or tri... trilateral? symmetry. Limbs and digits and sensory organs will come in threes. Three, six, or nine limbs/digits being the most common, along with three eyes, etc. (This means, by the by, that it could evolve dragons! Whee!)

The primary significance of this is that occasionally, some of these trinary creatures will make their way over to the binary continent, fueling the mythologies and legends of the elves. Three will be a significant number, but associated with monsters and the unnatural. Two and four, on the other hand, will have positive significance.

Planety Goodness and the Darkest Hours

So I've pretty much decided that this is going to be a moon of a gas giant at this point. Which of course gives me a whole other set of things to decide!

First, of course, is the obliquity of the planet's rotation. The reason this is important is that it determines the relative inclination of the moon's revolution about the planet, and thus directly affects a) the seasons, and b) the eclipses. (The obliquity is the angle of the axis, relative to the orbital plane.)

There are a lot of eclipses.

The moon is tidally locked to the gas giant, meaning each day/night cycle is a single revolution about the planet. Probably somewhere in the vicinity of one of our weeks. Now, what this means is that every single day, the planet will eclipse the sun. The only case in which it wouldn't is if the planet has a pretty large obliquity, in which case it would only eclipse a few times a year or something.

Now, this doesn't have to be a complete eclipse every day. It could just be a partial eclipse. It depends on your location on the moon's surface and on the planet's obliquity/inclination of the moon's orbital plane. (Picture, if you will, the vast curve of the planet overhead, part of it eternally dipping below the horizon. Every day, the sun rises in the east, soaring across the sky. At the apex of its daily arc, it slowly dips behind the great planet, sending the world into a noontime darkness. And this is a perfectly normal and regular occurrence!)

Another interesting part of being a large moon orbiting a gas giant is that you can see your moon's shadow on the surface of the planet in the sky.

An interesting biological/evolutionary aspect of this is that there is no real concept of nocturnal or diurnal, because the length of the night or day is entirely too long to sleep through most of either of them. Animals will need to be functional in both times of day.

On the flip side of that, the planet itself will reflect quite a lot of light down during the night, so it never gets very dark. Except at noon! The darkest time of the day/night cycle.