Why Do Rabbits Dig Burrows? — And How That Burrow Became a Game
Mocha endlessly digging her way down isn't pure fantasy.
There really are rabbits that dig into the ground and live inside it: the European rabbit, which also happens to be the ancestor of the pet rabbits we keep at home.
The burrows they dig aren't simple holes, but something closer to an underground city, with many entrances and tunnels woven together like a spiderweb.
In English, this whole network of burrows is called a "warren." Inside, there are separate chambers for sleeping and for raising young, and it's all designed so that when danger strikes, the rabbits can scatter and flee through multiple exits.
The burrow is both home and shelter for a rabbit.
Up on the surface there are plenty of predators hunting them, but it's hard for those predators to chase a rabbit deep into a narrow tunnel.
Underground is also far more stable for escaping the heat of midsummer and the cold of midwinter.
What's interesting is that not all rabbits dig burrows.
Species like North America's cottontail tend to hide in thickets or borrow holes others have already dug, rather than digging their own.
Diligently turning over the earth is really the burrowing rabbit's specialty.
Why the branching paths had to go
From here on, these are the choices I made turning that burrow into a game.
The first thing I gave up was the branching that defines a warren.
Real burrows split and lead into chambers, and building that faithfully produces a maze game rather than a runner.
Every fork makes the player stop to ask which way is right, and the sense of speed dies in that pause.
What this game sells is the fun of reacting quickly, so the path stays single and fixed.
Instead I made the burrow bend continuously left and right.
Even without forks, anything that isn't straight reads as dug by hand.
The difference between a pipe bored along a ruler and a tunnel clawed downward is really that irregularity.
The curve isn't drawn in advance either — it's a few sine waves layered together, so no matter how deep you go the same shape never repeats.
What being round gave me
The fact that a burrow is round I leaned into rather than worked around.
A typical runner has you on a floor moving between three lanes; here Mocha can run anywhere around the tunnel's circumference, including upside down along what would be the ceiling.
That's not decoration, it followed naturally from the setting.
And once the space you can move through is a circle rather than a line, the ways an obstacle can be placed get far more varied.
The things in the soil
Real burrows go through soil, which means running into tree roots.
So roots became the signature obstacle.
A root is an arc across the tunnel's circumference, so you can't slip around it sideways — you have to jump.
That "no sideways escape" property creates a different kind of decision than a rock does.
The scatter on the walls came from the same thinking.
Pebbles, dark patches of soil, mushrooms, and drifting fireflies are laid out differently in every section.
Without them the tunnel reads as a smooth cylinder, which feels extruded rather than excavated.
They have no effect on play at all, but they're what says you are inside earth.
Mocha, it seems, inherited that hard-working bloodline.
Her burrow is just far simpler than a real warren, and far deeper.